I cannot upload reliably (if at all) the group avatar and cover photo for groups I have set up. I have noted previous posters having the same problem with a fix in the current version to address it. If that was the case then I have a different problem with the same symptoms.
Log into the system then components/easysocial/groups and try to upload image files. The cover does load but the group avatar just sits there and doesn't complete. If I try to save I get a disconnect error.
Saving just the cover works as you will see if you check your local group