I’m on mobile device, and when I try to set an avatar for a certain picture it sends me to a new tab named “JavaScript:Void” Would I have to be on the PC site or is there something wrong with the mobile site?

I use mostly mobile and never had issues setting an Avatar, the only time I had problems was when I marked the checkbox(do not show it again) that appears when setting an Avatar when this get marked I can't set a post as avatar anymore, maybe you did the same thing?

Alternatively you can copy the post id go to Account --> Settings --> Basic --> Avatar post id --> Paste the id there --> Submit/Save settings to set a post as an avatar.

Sorry about the late reply but thanks so much for the help! I put the id in and it worked! :3