Each drag tick changed the edited photo's settings, so the filmstrip asked
for a new thumbnail render every frame. For an unedited raw shown with its
embedded preview, the thumbnail-level source had never been decoded, so each
of those renders decoded the whole raw (a 64 MP ARW: over a second), several
side by side, and the loupe's drafts queued behind them.
- The edited photo's thumbnail is not re-rendered during a slider drag while
it has one; it follows once the drag ends.
- A thumbnail of a photo whose preview-level source is decoded (the one in
the loupe) is cut from that source (SourceRef::Fit) instead of decoding the
file again; not when the photo has a denoised picture.
Co-Authored-By: Claude <noreply@anthropic.com>
