how to add pictures?

(also did this as bulletin but figured i should post here too) pretty much any time i try to add a pic here that's not my profile pic i get one of those broken picture thumbnails. does anyone know how to fix this? i would love to add cute pics and gifs to my profile and share stuff with you guys. my friend hannah doesn't really seem to have any issues, is it because my account is older? please help! thanks!!