the GIF format is no longer used because the WebP format is used instead. so i would like to not put GIF files in my submission.

i plan to put my assets in these 2 common image formats:

1. WebP, the most modern format that’s supported by most widely-used programs today
2. PNG, for use with some older but still widely-used programs

Yeah, there in the description were just several most common formats. The poin isn't in the fact that you need to use all those formats. The point is you need to add files in "common" formats not just specialized program formats (ase, psd, xcf). Submission must contain files that can be opened without special software just simple image viewer...

About gif. It is still used for simple(st) pixel art