A `.tif` in an album drew nothing: the tile took the file's embedded JPEG —
which a TIFF has not got, so the search found the frame's own pixel data and
kept three hundred kilobytes of it as the frame's tile — and nothing else in
the app draws a TIFF either, `createImageBitmap` answering InvalidStateError
and CanvasKit's `MakeImageFromEncoded` answering null to one.
`src/engine/tiffDecode.ts` reads the file itself, strips or tiles, and hands
back a shrunk frame, which is what the tile is made of now. The tiles that
were kept are dropped once (v4) so a frame already looked at is drawn right.
