fix(snapshots): Support jpg/jpeg in diff command

The diff command only collected .png files, but the upload command
supports png, jpg, and jpeg. Align the diff command to match.

Co-Authored-By: Claude <noreply@anthropic.com>

Author: NicoHinderling

src/commands/snapshots/diff.rs

@@ -141,8 +141,8 @@ pub fn execute(matches: &ArgMatches) -> Result<()> {
         bail!("Head directory does not exist: {}", head_dir.display());
     }
 
-    let base_files = collect_png_files(&base_dir)?;
-    let head_files = collect_png_files(&head_dir)?;
+    let base_files = collect_image_files(&base_dir)?;
+    let head_files = collect_image_files(&head_dir)?;
     let categorized = categorize_images(&base_files, &head_files);
 
     let output_diff_mask = true;
@@ -351,20 +351,26 @@ pub fn execute(matches: &ArgMatches) -> Result<()> {
     Ok(())
 }
 
-fn collect_png_files(dir: &Path) -> Result<BTreeSet<PathBuf>> {
+const IMAGE_EXTENSIONS: &[&str] = &["png", "jpg", "jpeg"];
+
+fn collect_image_files(dir: &Path) -> Result<BTreeSet<PathBuf>> {
     let mut files = BTreeSet::new();
     for entry in WalkDir::new(dir).follow_links(true) {
         let entry = entry?;
         if !entry.file_type().is_file() {
             continue;
         }
         let path = entry.path();
-        let is_png = path
+        let is_image = path
             .extension()
             .and_then(|e| e.to_str())
-            .map(|e| e.eq_ignore_ascii_case("png"))
+            .map(|e| {
+                IMAGE_EXTENSIONS
+                    .iter()
+                    .any(|ext| e.eq_ignore_ascii_case(ext))
+            })
             .unwrap_or(false);
-        if is_png {
+        if is_image {
             let rel = path.strip_prefix(dir)?.to_path_buf();
             files.insert(rel);
         }