The experts in the forum may be able to guide you if you can specify the exact issue that you are experiencing or what you are actually looking for?
There is always content included in the Jabber planning guide on the respected releases related to contact photo requirements and specifications.
It is the same issue, as described in this thread: https://community.cisco.com/t5/collaboration-voice-and-video/jabber-displays-cached-contact-photo/ta-p/3118150
I wonder if there is something (Parameter) in Jabber to delete the photo cache to have actual contact photos.
Years ago there was also an enhancement request to fix this issue: https://bst.cloudapps.cisco.com/bugsearch/bug/CSCtu25084
It's still that unfortunately, as best I can tell.
I sort of remember someone talking about a workaround by changing the parameter for where the avatar is, but that was with a web server.
I planned to tackle this myself by having my scripting which pulls pictures for avatars generate one based on the user's initials, back when Jabber only showed a silhouette. The client then eventually updated to do this itself and I put that on the way back burner. That's the only other way I can think of to force it forward. If the avatar changes, it will update it eventually when refreshing the contact but it will not remove it, it seems.