I'd love being able to just upload my 4.6MB image and getting it reduced down to sub 2MB, but I have to do that manually because Jerboa & co doesn't do it nor accept bigger images than 2MB.
Naah, Upload limit is instance wise like lemm.ee have 500kb. So, no it will not take 1mb file and reduce it to 500kb or less. That's why I don't even rely on default lemm.ee image upload. I just use my paid private image hoster.
I have my own lemmy instance with pictrs, still can't use bigger images. Maybe it's a hard limit or else every other instance will deny the "too big image"?
I'm okay with that limit, it's just a hassle you can't share a bigger image and have it reduced in size automatically.