Am I doing it right/wrong? Sounds like an imagemagick issue, not something with Phabricator.

It looks like something to do with {meme, src=foo} vs just foo

Ah, I didn't realize people were using the {meme}Remarkup without text. I don't know if transparency is supported with that, we'll have to investigate.

◀ Merged tasks: T5974.

I wasn't able to reproduce the black background issue, exactly, but here's what I changed:

For comparison, here's the original GIF:

Prior to D19214, this appeared to turn into this GIF when mangled through the meme pipeline. There's no black background, but the frames are piling up on top of one another:

After D19214, we use -dispose background to wipe frames before repainting them, which produces this GIF:

Because we split the frames out with -coalesce, which should fully rasterize each frame, this change should be safe even for GIFs which rely on -dispose none.

Note that although the pixels are correct for each frame now, the mangled GIF isn't perfect: the frame rate has changed since we've lost the delay metadata. I think this is hard to fix, so I don't currently plan to fix this.

This should also work with overlay text:

{meme, src= tatsumakisenpukyaku, below=hundred hand slap}