Enh, it’s hard to say. The body shapes are certainly similar, but generally I like to have something a little more concrete (like a mole, scar, tattoo, etc or credible written source) to make a match like that.

No clue, I know Lemmy likes webp since it helps cut down on storage costs, but I’ve never dug into the mechanics of how it’s set up. Op’s image could also be suffering from repeated compressions as it’s been uploaded/ downloaded/ re-encoded and passed around the Internet.