diff --git a/src/kra.rs b/src/kra.rs
index 5e3d626..3642370 100644
--- a/src/kra.rs
+++ b/src/kra.rs
@@ -15,19 +15,9 @@ pub fn register() -> bool {
 }
 
 fn hook<'a>(reader: GenericReader<'a>) -> ImageResult<Box<dyn ImageDecoder + 'a>> {
-    let mut zip = ZipArchive::new(reader).map_err(|e| {
-        ImageError::Decoding(DecodingError::new(
-            image::error::ImageFormatHint::PathExtension("kra".into()),
-            e,
-        ))
-    })?;
+    let mut zip = ZipArchive::new(reader).map_err(to_image_error)?;
 
-    let mut reader = zip.by_name("mergedimage.png").map_err(|e| {
-        ImageError::Decoding(DecodingError::new(
-            image::error::ImageFormatHint::PathExtension("kra".into()),
-            e,
-        ))
-    })?;
+    let mut reader = zip.by_name("mergedimage.png").map_err(to_image_error)?;
 
     // reading it all and wrapping it with a Cursor
     // is the only way I know to give it Seek
@@ -39,3 +29,12 @@ fn hook<'a>(reader: GenericReader<'a>) -> ImageResult<Box<dyn ImageDecoder + 'a>
 
     Ok(Box::new(image_reader.into_decoder()?))
 }
+
+fn to_image_error(
+    e: impl Into<Box<dyn std::error::Error + std::marker::Send + Sync + 'static>>,
+) -> ImageError {
+    ImageError::Decoding(DecodingError::new(
+        image::error::ImageFormatHint::PathExtension("kra".into()),
+        e,
+    ))
+}