diff --git a/Cargo.lock b/Cargo.lock
index 23052a870..b699d2450 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3039,6 +3039,7 @@ dependencies = [
  "icu_provider_blob",
  "icu_segmenter",
  "kurbo",
+ "memchr",
  "rustybuzz",
  "smallvec",
  "ttf-parser",
diff --git a/crates/typst-layout/Cargo.toml b/crates/typst-layout/Cargo.toml
index 438e09e43..cc355a3db 100644
--- a/crates/typst-layout/Cargo.toml
+++ b/crates/typst-layout/Cargo.toml
@@ -30,6 +30,7 @@ icu_provider_adapters = { workspace = true }
 icu_provider_blob = { workspace = true }
 icu_segmenter = { workspace = true }
 kurbo = { workspace = true }
+memchr = { workspace = true }
 rustybuzz = { workspace = true }
 smallvec = { workspace = true }
 ttf-parser = { workspace = true }
diff --git a/crates/typst-layout/src/image.rs b/crates/typst-layout/src/image.rs
index 8136a25a3..56eeaea09 100644
--- a/crates/typst-layout/src/image.rs
+++ b/crates/typst-layout/src/image.rs
@@ -1,6 +1,6 @@
 use std::ffi::OsStr;
 
-use typst_library::diag::{warning, At, SourceResult, StrResult};
+use typst_library::diag::{warning, At, LoadedAt, SourceResult, StrResult};
 use typst_library::engine::Engine;
 use typst_library::foundations::{Bytes, Derived, Packed, Smart, StyleChain};
 use typst_library::introspection::Locator;
@@ -30,14 +30,14 @@ pub fn layout_image(
     let Derived { source, derived: data } = &elem.source;
     let format = match elem.format(styles) {
         Smart::Custom(v) => v,
-        Smart::Auto => determine_format(source, data).at(span)?,
+        Smart::Auto => determine_format(source, &data.bytes).at(span)?,
     };
 
     // Warn the user if the image contains a foreign object. Not perfect
     // because the svg could also be encoded, but that's an edge case.
     if format == ImageFormat::Vector(VectorFormat::Svg) {
         let has_foreign_object =
-            data.as_str().is_ok_and(|s| s.contains("<foreignObject"));
+            memchr::memmem::find(&data.bytes, b"<foreignObject").is_some();
 
         if has_foreign_object {
             engine.sink.warn(warning!(
@@ -53,7 +53,7 @@ pub fn layout_image(
     let kind = match format {
         ImageFormat::Raster(format) => ImageKind::Raster(
             RasterImage::new(
-                data.clone(),
+                data.bytes.clone(),
                 format,
                 elem.icc(styles).as_ref().map(|icc| icc.derived.clone()),
             )
@@ -61,11 +61,11 @@ pub fn layout_image(
         ),
         ImageFormat::Vector(VectorFormat::Svg) => ImageKind::Svg(
             SvgImage::with_fonts(
-                data.clone(),
+                data.bytes.clone(),
                 engine.world,
                 &families(styles).map(|f| f.as_str()).collect::<Vec<_>>(),
             )
-            .at(span)?,
+            .in_text(&data)?,
         ),
     };
 
diff --git a/crates/typst-library/src/diag.rs b/crates/typst-library/src/diag.rs
index 6372c1c69..24b9b6e4e 100644
--- a/crates/typst-library/src/diag.rs
+++ b/crates/typst-library/src/diag.rs
@@ -570,8 +570,54 @@ impl From<PackageError> for EcoString {
     }
 }
 
-impl Loaded {
+pub type LoadResult<T> = Result<T, LoadError>;
+
+/// A callsite independent error that occurred during data loading.
+/// Can be turned into a [`SourceDiagnostic`] using the [`LoadedAt::in_text`]
+/// or [`LoadedAt::in_invalid_text`] methods available on [`LoadResult`].
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct LoadError {
+    pub pos: ReportPos,
+    pub message: EcoString,
+    pub error: EcoString,
+}
+
+impl LoadError {
+    pub fn new(
+        pos: impl Into<ReportPos>,
+        message: impl std::fmt::Display,
+        error: impl std::fmt::Display,
+    ) -> Self {
+        Self {
+            pos: pos.into(),
+            message: eco_format!("{message}"),
+            error: eco_format!("{error}"),
+        }
+    }
+}
+
+/// Convert a [`LoadResult`] to a [`SourceResult`] by adding the [`Loaded`] context.
+pub trait LoadedAt<T> {
+    /// Add the span information.
+    fn in_text(self, data: &Loaded) -> SourceResult<T>;
+
+    /// Add the span information.
+    fn in_invalid_text(self, data: &Loaded) -> SourceResult<T>;
+}
+
+impl<T> LoadedAt<T> for Result<T, LoadError> {
     /// Report an error, possibly in an external file.
+    fn in_text(self, data: &Loaded) -> SourceResult<T> {
+        self.map_err(|err| data.err_in_text(err.pos, err.message, err.error))
+    }
+
+    /// Report an error in invalid text.
+    fn in_invalid_text(self, data: &Loaded) -> SourceResult<T> {
+        self.map_err(|err| data.err_in_invalid_text(err.pos, err.message, err.error))
+    }
+}
+
+impl Loaded {
     pub fn err_in_text(
         &self,
         pos: impl Into<ReportPos>,
@@ -632,7 +678,7 @@ impl Loaded {
     }
 }
 
-#[derive(Clone, Debug, Default, PartialEq, Eq)]
+#[derive(Clone, Debug, Default, PartialEq, Eq, Hash)]
 pub enum ReportPos {
     /// Contains the range, and the 0-based line/column.
     Full(std::ops::Range<usize>, LineCol),
@@ -694,7 +740,7 @@ impl ReportPos {
 }
 
 /// A line/column pair.
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
 pub struct LineCol {
     /// The 0-based line.
     line: usize,
@@ -732,38 +778,34 @@ impl LineCol {
 
     /// Returns the 0-based line/column indices.
     pub fn indices(&self) -> (usize, usize) {
-        (self.line, self.col)
+        (self.line as usize, self.col as usize)
     }
 
     /// Returns the 1-based line/column numbers.
     pub fn numbers(&self) -> (usize, usize) {
-        (self.line + 1, self.col + 1)
+        (self.line as usize + 1, self.col as usize + 1)
     }
 }
 
 /// Format a user-facing error message for an XML-like file format.
-pub fn format_xml_like_error(
-    format: &str,
-    data: &Loaded,
-    error: roxmltree::Error,
-) -> EcoVec<SourceDiagnostic> {
+pub fn format_xml_like_error(format: &str, error: roxmltree::Error) -> LoadError {
     let pos = LineCol::one_based(error.pos().row as usize, error.pos().col as usize);
-    let msg = format!("failed to parse {format}");
+    let msg = eco_format!("failed to parse {format}");
     let err = match error {
         roxmltree::Error::UnexpectedCloseTag(expected, actual, _) => {
-            format!("found closing tag '{actual}' instead of '{expected}'")
+            eco_format!("found closing tag '{actual}' instead of '{expected}'")
         }
         roxmltree::Error::UnknownEntityReference(entity, _) => {
-            format!("unknown entity '{entity}'")
+            eco_format!("unknown entity '{entity}'")
         }
         roxmltree::Error::DuplicatedAttribute(attr, _) => {
-            format!("duplicate attribute '{attr}'")
+            eco_format!("duplicate attribute '{attr}'")
         }
         roxmltree::Error::NoRootNode => {
-            format!("missing root node")
+            eco_format!("missing root node")
         }
-        err => err.to_string(),
+        err => eco_format!("{err}"),
     };
 
-    data.err_in_text(pos, msg, err)
+    LoadError::new(pos, msg, err)
 }
diff --git a/crates/typst-library/src/loading/mod.rs b/crates/typst-library/src/loading/mod.rs
index eb3726e7d..259060a72 100644
--- a/crates/typst-library/src/loading/mod.rs
+++ b/crates/typst-library/src/loading/mod.rs
@@ -17,7 +17,7 @@ mod yaml_;
 
 use comemo::Tracked;
 use ecow::EcoString;
-use typst_syntax::{FileId, Span, Spanned};
+use typst_syntax::{FileId, Spanned};
 
 pub use self::cbor_::*;
 pub use self::csv_::*;
@@ -27,7 +27,7 @@ pub use self::toml_::*;
 pub use self::xml_::*;
 pub use self::yaml_::*;
 
-use crate::diag::{At, FileError, SourceResult};
+use crate::diag::{At, LoadError, LoadResult, LoadedAt, SourceResult};
 use crate::foundations::OneOrMultiple;
 use crate::foundations::{cast, Bytes, Scope, Str};
 use crate::World;
@@ -121,46 +121,47 @@ impl Load for Spanned<&OneOrMultiple<DataSource>> {
 }
 
 /// Data loaded from a [`DataSource`].
-#[derive(Clone, Hash)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Loaded {
     pub source: Spanned<LoadSource>,
     pub bytes: Bytes,
 }
 
 impl Loaded {
-    /// FIXME: remove this?
-    pub fn dummy() -> Self {
-        Loaded::new(
-            typst_syntax::Spanned::new(LoadSource::Bytes, Span::detached()),
-            Bytes::new([]),
-        )
-    }
-
     pub fn new(source: Spanned<LoadSource>, bytes: Bytes) -> Self {
         Self { source, bytes }
     }
 
-    pub fn as_str(&self) -> SourceResult<&str> {
-        self.bytes.as_str().map_err(|err| {
-            let start = err.valid_up_to();
-            let end = start + err.error_len().unwrap_or(0);
-            // always report this error in the source file.
-            self.err_in_invalid_text(
-                start..end,
-                "failed to convert to string",
-                FileError::from(err),
-            )
-        })
+    pub fn load_str(&self) -> SourceResult<&str> {
+        self.bytes.load_str().in_invalid_text(self)
     }
 }
 
 /// A loaded [`DataSource`].
-#[derive(Clone, Copy, Hash)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
 pub enum LoadSource {
     Path(FileId),
     Bytes,
 }
 
+pub trait LoadStr {
+    fn load_str(&self) -> LoadResult<&str>;
+}
+
+impl<T: AsRef<[u8]>> LoadStr for T {
+    fn load_str(&self) -> LoadResult<&str> {
+        std::str::from_utf8(self.as_ref()).map_err(|err| {
+            let start = err.valid_up_to();
+            let end = start + err.error_len().unwrap_or(0);
+            LoadError::new(
+                start..end,
+                "failed to convert to string",
+                "file is not valid utf-8",
+            )
+        })
+    }
+}
+
 /// A value that can be read from a file.
 #[derive(Debug, Clone, PartialEq, Hash)]
 pub enum Readable {
diff --git a/crates/typst-library/src/loading/read.rs b/crates/typst-library/src/loading/read.rs
index 118ed681a..94082a424 100644
--- a/crates/typst-library/src/loading/read.rs
+++ b/crates/typst-library/src/loading/read.rs
@@ -38,7 +38,7 @@ pub fn read(
     let data = path.map(DataSource::Path).load(engine.world)?;
     Ok(match encoding {
         None => Readable::Bytes(data.bytes),
-        Some(Encoding::Utf8) => Readable::Str(data.as_str()?.into()),
+        Some(Encoding::Utf8) => Readable::Str(data.load_str()?.into()),
     })
 }
 
diff --git a/crates/typst-library/src/loading/toml.rs b/crates/typst-library/src/loading/toml.rs
index f20de9064..38ee39c41 100644
--- a/crates/typst-library/src/loading/toml.rs
+++ b/crates/typst-library/src/loading/toml.rs
@@ -1,10 +1,10 @@
-use ecow::{eco_format, EcoVec};
+use ecow::eco_format;
 use typst_syntax::Spanned;
 
-use crate::diag::{At, ReportPos, SourceDiagnostic, SourceResult};
+use crate::diag::{At, LoadError, LoadedAt, ReportPos, SourceResult};
 use crate::engine::Engine;
 use crate::foundations::{func, scope, Str, Value};
-use crate::loading::{DataSource, Load, Loaded, Readable};
+use crate::loading::{DataSource, Load, Readable};
 
 /// Reads structured data from a TOML file.
 ///
@@ -33,8 +33,8 @@ pub fn toml(
     source: Spanned<DataSource>,
 ) -> SourceResult<Value> {
     let data = source.load(engine.world)?;
-    let raw = data.as_str()?;
-    ::toml::from_str(raw).map_err(|err| format_toml_error(&data, err))
+    let raw = data.load_str()?;
+    ::toml::from_str(raw).map_err(format_toml_error).in_text(&data)
 }
 
 #[scope]
@@ -69,10 +69,7 @@ impl toml {
 }
 
 /// Format the user-facing TOML error message.
-fn format_toml_error(
-    data: &Loaded,
-    error: ::toml::de::Error,
-) -> EcoVec<SourceDiagnostic> {
-    let pos = error.span().map(ReportPos::Range).unwrap_or_default();
-    data.err_in_text(pos, "failed to parse TOML", error.message())
+fn format_toml_error(error: ::toml::de::Error) -> LoadError {
+    let pos = error.span().map(ReportPos::from).unwrap_or_default();
+    LoadError::new(pos, "failed to parse TOML", error.message())
 }
diff --git a/crates/typst-library/src/loading/xml.rs b/crates/typst-library/src/loading/xml.rs
index 170a29b29..623bad3ea 100644
--- a/crates/typst-library/src/loading/xml.rs
+++ b/crates/typst-library/src/loading/xml.rs
@@ -1,11 +1,10 @@
-use ecow::EcoVec;
 use roxmltree::ParsingOptions;
 use typst_syntax::Spanned;
 
-use crate::diag::{format_xml_like_error, SourceDiagnostic, SourceResult};
+use crate::diag::{format_xml_like_error, LoadError, LoadedAt, SourceResult};
 use crate::engine::Engine;
 use crate::foundations::{dict, func, scope, Array, Dict, IntoValue, Str, Value};
-use crate::loading::{DataSource, Load, Loaded, Readable};
+use crate::loading::{DataSource, Load, Readable};
 
 /// Reads structured data from an XML file.
 ///
@@ -62,12 +61,13 @@ pub fn xml(
     source: Spanned<DataSource>,
 ) -> SourceResult<Value> {
     let data = source.load(engine.world)?;
-    let text = data.as_str()?;
+    let text = data.load_str()?;
     let document = roxmltree::Document::parse_with_options(
         text,
         ParsingOptions { allow_dtd: true, ..Default::default() },
     )
-    .map_err(|err| format_xml_error(&data, err))?;
+    .map_err(format_xml_error)
+    .in_text(&data)?;
     Ok(convert_xml(document.root()))
 }
 
@@ -110,6 +110,6 @@ fn convert_xml(node: roxmltree::Node) -> Value {
 }
 
 /// Format the user-facing XML error message.
-fn format_xml_error(data: &Loaded, error: roxmltree::Error) -> EcoVec<SourceDiagnostic> {
-    format_xml_like_error("XML", data, error)
+fn format_xml_error(error: roxmltree::Error) -> LoadError {
+    format_xml_like_error("XML", error)
 }
diff --git a/crates/typst-library/src/model/bibliography.rs b/crates/typst-library/src/model/bibliography.rs
index 4b8235663..6c447ff1e 100644
--- a/crates/typst-library/src/model/bibliography.rs
+++ b/crates/typst-library/src/model/bibliography.rs
@@ -20,8 +20,8 @@ use typst_syntax::{Span, Spanned};
 use typst_utils::{Get, ManuallyHash, NonZeroExt, PicoStr};
 
 use crate::diag::{
-    bail, error, At, HintedStrResult, ReportPos, SourceDiagnostic, SourceResult,
-    StrResult,
+    bail, error, At, HintedStrResult, LoadError, LoadResult, LoadedAt, ReportPos,
+    SourceDiagnostic, SourceResult, StrResult,
 };
 use crate::engine::{Engine, Sink};
 use crate::foundations::{
@@ -34,7 +34,7 @@ use crate::layout::{
     BlockBody, BlockElem, Em, GridCell, GridChild, GridElem, GridItem, HElem, PadElem,
     Sides, Sizing, TrackSizings,
 };
-use crate::loading::{format_yaml_error, DataSource, Load, LoadSource, Loaded};
+use crate::loading::{format_yaml_error, DataSource, Load, LoadSource, LoadStr, Loaded};
 use crate::model::{
     CitationForm, CiteGroup, Destination, FootnoteElem, HeadingElem, LinkElem, ParElem,
     Url,
@@ -356,7 +356,7 @@ impl Debug for Bibliography {
 
 /// Decode on library from one data source.
 fn decode_library(data: &Loaded) -> SourceResult<Library> {
-    let str = data.as_str()?;
+    let str = data.load_str()?;
 
     if let LoadSource::Path(file_id) = data.source.v {
         // If we got a path, use the extension to determine whether it is
@@ -451,7 +451,7 @@ impl CslStyle {
             CslSource::Named(style) => Self::from_archived(*style),
             CslSource::Normal(source) => {
                 let data = Spanned::new(source, span).load(world)?;
-                Self::from_data(&data)?
+                Self::from_data(&data.bytes).in_text(&data)?
             }
         };
         Ok(Derived::new(source, style))
@@ -472,17 +472,17 @@ impl CslStyle {
 
     /// Load a CSL style from file contents.
     #[comemo::memoize]
-    pub fn from_data(data: &Loaded) -> SourceResult<CslStyle> {
-        let text = data.as_str()?;
+    pub fn from_data(bytes: &Bytes) -> LoadResult<CslStyle> {
+        let text = bytes.load_str()?;
         citationberg::IndependentStyle::from_xml(text)
             .map(|style| {
                 Self(Arc::new(ManuallyHash::new(
                     style,
-                    typst_utils::hash128(&(TypeId::of::<Bytes>(), data)),
+                    typst_utils::hash128(&(TypeId::of::<Bytes>(), bytes)),
                 )))
             })
             .map_err(|err| {
-                data.err_in_text(ReportPos::None, "failed to load CSL style", err)
+                LoadError::new(ReportPos::None, "failed to load CSL style", err)
             })
     }
 
diff --git a/crates/typst-library/src/text/raw.rs b/crates/typst-library/src/text/raw.rs
index 8ce920b21..a8dbbdfdd 100644
--- a/crates/typst-library/src/text/raw.rs
+++ b/crates/typst-library/src/text/raw.rs
@@ -11,15 +11,15 @@ use typst_utils::ManuallyHash;
 use unicode_segmentation::UnicodeSegmentation;
 
 use super::Lang;
-use crate::diag::{LineCol, ReportPos, SourceDiagnostic, SourceResult};
+use crate::diag::{LineCol, LoadError, LoadResult, LoadedAt, ReportPos, SourceResult};
 use crate::engine::Engine;
 use crate::foundations::{
-    cast, elem, scope, Content, Derived, NativeElement, OneOrMultiple, Packed, PlainText,
-    Show, ShowSet, Smart, StyleChain, Styles, Synthesize, TargetElem,
+    cast, elem, scope, Bytes, Content, Derived, NativeElement, OneOrMultiple, Packed,
+    PlainText, Show, ShowSet, Smart, StyleChain, Styles, Synthesize, TargetElem,
 };
 use crate::html::{tag, HtmlElem};
 use crate::layout::{BlockBody, BlockElem, Em, HAlignment};
-use crate::loading::{DataSource, Load, Loaded};
+use crate::loading::{DataSource, Load, LoadStr};
 use crate::model::{Figurable, ParElem};
 use crate::text::{FontFamily, FontList, LinebreakElem, LocalName, TextElem, TextSize};
 use crate::visualize::Color;
@@ -540,25 +540,28 @@ impl RawSyntax {
         sources: Spanned<OneOrMultiple<DataSource>>,
     ) -> SourceResult<Derived<OneOrMultiple<DataSource>, Vec<RawSyntax>>> {
         let data = sources.load(world)?;
-        let list = data.iter().map(Self::decode).collect::<SourceResult<_>>()?;
+        let list = data
+            .iter()
+            .map(|data| Self::decode(&data.bytes).in_text(data))
+            .collect::<SourceResult<_>>()?;
         Ok(Derived::new(sources.v, list))
     }
 
     /// Decode a syntax from a loaded source.
     #[comemo::memoize]
     #[typst_macros::time(name = "load syntaxes")]
-    fn decode(data: &Loaded) -> SourceResult<RawSyntax> {
-        let str = data.as_str()?;
+    fn decode(bytes: &Bytes) -> LoadResult<RawSyntax> {
+        let str = bytes.load_str()?;
 
         let syntax = SyntaxDefinition::load_from_str(str, false, None)
-            .map_err(|err| format_syntax_error(data, err))?;
+            .map_err(format_syntax_error)?;
 
         let mut builder = SyntaxSetBuilder::new();
         builder.add(syntax);
 
         Ok(RawSyntax(Arc::new(ManuallyHash::new(
             builder.build(),
-            typst_utils::hash128(data),
+            typst_utils::hash128(bytes),
         ))))
     }
 
@@ -568,12 +571,9 @@ impl RawSyntax {
     }
 }
 
-fn format_syntax_error(
-    data: &Loaded,
-    error: ParseSyntaxError,
-) -> EcoVec<SourceDiagnostic> {
+fn format_syntax_error(error: ParseSyntaxError) -> LoadError {
     let pos = syntax_error_pos(&error);
-    data.err_in_text(pos, "failed to parse syntax", error)
+    LoadError::new(pos, "failed to parse syntax", error)
 }
 
 fn syntax_error_pos(error: &ParseSyntaxError) -> ReportPos {
@@ -600,17 +600,17 @@ impl RawTheme {
         source: Spanned<DataSource>,
     ) -> SourceResult<Derived<DataSource, Self>> {
         let data = source.load(world)?;
-        let theme = Self::decode(&data)?;
+        let theme = Self::decode(&data.bytes).in_text(&data)?;
         Ok(Derived::new(source.v, theme))
     }
 
     /// Decode a theme from bytes.
     #[comemo::memoize]
-    fn decode(data: &Loaded) -> SourceResult<RawTheme> {
-        let mut cursor = std::io::Cursor::new(data.bytes.as_slice());
-        let theme = synt::ThemeSet::load_from_reader(&mut cursor)
-            .map_err(|err| format_theme_error(data, err))?;
-        Ok(RawTheme(Arc::new(ManuallyHash::new(theme, typst_utils::hash128(data)))))
+    fn decode(bytes: &Bytes) -> LoadResult<RawTheme> {
+        let mut cursor = std::io::Cursor::new(bytes.as_slice());
+        let theme =
+            synt::ThemeSet::load_from_reader(&mut cursor).map_err(format_theme_error)?;
+        Ok(RawTheme(Arc::new(ManuallyHash::new(theme, typst_utils::hash128(bytes)))))
     }
 
     /// Get the underlying syntect theme.
@@ -619,15 +619,12 @@ impl RawTheme {
     }
 }
 
-fn format_theme_error(
-    data: &Loaded,
-    error: syntect::LoadingError,
-) -> EcoVec<SourceDiagnostic> {
+fn format_theme_error(error: syntect::LoadingError) -> LoadError {
     let pos = match &error {
         syntect::LoadingError::ParseSyntax(err, _) => syntax_error_pos(err),
         _ => ReportPos::None,
     };
-    data.err_in_text(pos, "failed to parse theme", error)
+    LoadError::new(pos, "failed to parse theme", error)
 }
 
 /// A highlighted line of raw text.
diff --git a/crates/typst-library/src/visualize/image/mod.rs b/crates/typst-library/src/visualize/image/mod.rs
index 387c43b4a..47505c10a 100644
--- a/crates/typst-library/src/visualize/image/mod.rs
+++ b/crates/typst-library/src/visualize/image/mod.rs
@@ -22,7 +22,7 @@ use crate::foundations::{
     Smart, StyleChain,
 };
 use crate::layout::{BlockElem, Length, Rel, Sizing};
-use crate::loading::{DataSource, Load, Readable};
+use crate::loading::{DataSource, Load, LoadSource, Loaded, Readable};
 use crate::model::Figurable;
 use crate::text::LocalName;
 
@@ -66,9 +66,9 @@ pub struct ImageElem {
     #[parse(
         let source = args.expect::<Spanned<DataSource>>("source")?;
         let data = source.load(engine.world)?;
-        Derived::new(source.v, data.bytes)
+        Derived::new(source.v, data)
     )]
-    pub source: Derived<DataSource, Bytes>,
+    pub source: Derived<DataSource, Loaded>,
 
     /// The image's format.
     ///
@@ -173,7 +173,7 @@ impl ImageElem {
     pub fn decode(
         span: Span,
         /// The data to decode as an image. Can be a string for SVGs.
-        data: Readable,
+        data: Spanned<Readable>,
         /// The image's format. Detected automatically by default.
         #[named]
         format: Option<Smart<ImageFormat>>,
@@ -193,8 +193,9 @@ impl ImageElem {
         #[named]
         scaling: Option<Smart<ImageScaling>>,
     ) -> StrResult<Content> {
-        let bytes = data.into_bytes();
-        let source = Derived::new(DataSource::Bytes(bytes.clone()), bytes);
+        let bytes = data.v.into_bytes();
+        let data = Loaded::new(Spanned::new(LoadSource::Bytes, data.span), bytes.clone());
+        let source = Derived::new(DataSource::Bytes(bytes), data);
         let mut elem = ImageElem::new(source);
         if let Some(format) = format {
             elem.push_format(format);
diff --git a/crates/typst-library/src/visualize/image/svg.rs b/crates/typst-library/src/visualize/image/svg.rs
index 787f7e0bc..1a3f6d474 100644
--- a/crates/typst-library/src/visualize/image/svg.rs
+++ b/crates/typst-library/src/visualize/image/svg.rs
@@ -3,13 +3,11 @@ use std::hash::{Hash, Hasher};
 use std::sync::{Arc, Mutex};
 
 use comemo::Tracked;
-use ecow::EcoString;
 use siphasher::sip128::{Hasher128, SipHasher13};
 
-use crate::diag::{format_xml_like_error, StrResult};
+use crate::diag::{format_xml_like_error, LoadError, LoadResult, ReportPos};
 use crate::foundations::Bytes;
 use crate::layout::Axes;
-use crate::loading::Loaded;
 use crate::text::{
     Font, FontBook, FontFlags, FontStretch, FontStyle, FontVariant, FontWeight,
 };
@@ -31,7 +29,7 @@ impl SvgImage {
     /// Decode an SVG image without fonts.
     #[comemo::memoize]
     #[typst_macros::time(name = "load svg")]
-    pub fn new(data: Bytes) -> StrResult<SvgImage> {
+    pub fn new(data: Bytes) -> LoadResult<SvgImage> {
         let tree =
             usvg::Tree::from_data(&data, &base_options()).map_err(format_usvg_error)?;
         Ok(Self(Arc::new(Repr { data, size: tree_size(&tree), font_hash: 0, tree })))
@@ -44,7 +42,7 @@ impl SvgImage {
         data: Bytes,
         world: Tracked<dyn World + '_>,
         families: &[&str],
-    ) -> StrResult<SvgImage> {
+    ) -> LoadResult<SvgImage> {
         let book = world.book();
         let resolver = Mutex::new(FontResolver::new(world, book, families));
         let tree = usvg::Tree::from_data(
@@ -126,21 +124,15 @@ fn tree_size(tree: &usvg::Tree) -> Axes<f64> {
 }
 
 /// Format the user-facing SVG decoding error message.
-fn format_usvg_error(error: usvg::Error) -> EcoString {
-    match error {
-        usvg::Error::NotAnUtf8Str => "file is not valid utf-8".into(),
-        usvg::Error::MalformedGZip => "file is not compressed correctly".into(),
-        usvg::Error::ElementsLimitReached => "file is too large".into(),
-        usvg::Error::InvalidSize => {
-            "failed to parse SVG (width, height, or viewbox is invalid)".into()
-        }
-        usvg::Error::ParsingFailed(error) => {
-            format_xml_like_error("SVG", &Loaded::dummy(), error)
-                .pop()
-                .expect("at least one error")
-                .message
-        }
-    }
+fn format_usvg_error(error: usvg::Error) -> LoadError {
+    let error = match error {
+        usvg::Error::NotAnUtf8Str => "file is not valid utf-8",
+        usvg::Error::MalformedGZip => "file is not compressed correctly",
+        usvg::Error::ElementsLimitReached => "file is too large",
+        usvg::Error::InvalidSize => "width, height, or viewbox is invalid",
+        usvg::Error::ParsingFailed(error) => return format_xml_like_error("SVG", error),
+    };
+    LoadError::new(ReportPos::None, "failed to parse SVG", error)
 }
 
 /// Provides Typst's fonts to usvg.