Comment #1 on issue 530 by pasca...@gmail.com
: Animated graph decoding failedhttps://bugs.chromium.org/p/webp/issues/detail?id=530#c1
The attached image is in PNG format, not in WebP format.
'vwebp.exe' agrees with that:
> vwebp attachment-509943.dat
Input file doesn't appear to be WebP format.
If you've converted this attachment to an animated-WebP file, then it's correct that 'dwebp' doesn't handle animated-WebP.
You need to use the 'anim_dump' tool (from examples/) to save individual frames of an animated-WebP.