Profile photos are turned off. Stop trying.
Following severals (error) messages with the text "The file you uploaded is too large" in the section "Paint.NET Forum > Your control panel > Profile > Change Photo" could it be possible to inform the (new) members that it is not possible to upload a personal photo.
At the moment it only states:
It took me (and maybe other members too) some time to figure out, that it was not possible.