Import: Purge frees decoded GIFs; a browser tab keeps less of one GIF (#567 follow-up)

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01QiAJeFttZp83Fh7YuzAR5f

crates/media/src/gif_anim.rs

@@ -15,8 +15,12 @@ use crate::{MediaError, Result};
 /// The `Footage::codec` of an animated GIF.
 pub(crate) const CODEC: &str = "GIF";
 
-/// Decoded frames of one GIF are kept as 8-bit RGBA, up to this many bytes.
+/// Decoded frames of one GIF are kept as 8-bit RGBA, up to this many bytes (less in a browser tab,
+/// whose wasm32 heap is 4 GiB at most and shared with everything else).
+#[cfg(not(target_arch = "wasm32"))]
 const MAX_BYTES: usize = 1 << 30;
+#[cfg(target_arch = "wasm32")]
+const MAX_BYTES: usize = 256 << 20;
 
 /// Frames read from a GIF's headers when probing.
 const MAX_FRAMES: usize = 100_000;

crates/media/src/pool.rs

@@ -304,13 +304,15 @@ impl MediaPool {
         let mut c = lock(&self.inner.cache);
         c.lru = Lru::default();
         c.last.clear();
+        drop(c);
+        // Decoded GIFs sit outside the frame budget; Purge frees them too.
+        lock(&self.inner.gifs).clear();
     }
 
     /// Drop every cached frame and decoder.
     pub fn clear(&self) {
         self.clear_frames();
         lock(&self.inner.sources).clear();
-        lock(&self.inner.gifs).clear();
     }
 
     /// Forget a file (after it changed on disk, or to retry a file that failed to open).