Strictly-speaking, last time I took a serious look at this, which was quite some years back, it was possible to make very small GIFs that were smaller than very small PNGs.
That used to be more significant back when “web bugs” – one-pixel, transparent images – were a popular mechanism to try to track users. I don’t know if that’s still a popular tactic these days.
I don’t know, because it sucks and has zero benefits over PNG?
Especially after animated pngs were developed but nobody wanted to support those so we’re stuck with gifs that are actually mp4s or webms.
Strictly-speaking, last time I took a serious look at this, which was quite some years back, it was possible to make very small GIFs that were smaller than very small PNGs.
That used to be more significant back when “web bugs” – one-pixel, transparent images – were a popular mechanism to try to track users. I don’t know if that’s still a popular tactic these days.
It is, they are called canvas now. I recommend Canvas Blocker addon (doesn’t block them but falsifies them).