Maybe you should try a different profile pic? Sometimes photos online can be wacky like that. It could also be in a bad format. I usually download photos and save them on my desktop. Usually this way it let's me set up profile pics.
i manually put it myself. the instance here is considerably closer to upstream lemmy than what hexbear seems to be running
there were some talk of modifications here but one of the admins got into an accident and is afaik still recovering and dealing with more important stuff (moving to cheaper hosting for one)
honestly it's a miracle this instance is as stable as it is given all the circumstances