Unfortunately at the moment this seems not possible using the Jive apps or Jive mobile version.
There's no default option to add or edit anything on the user profile at all using the Jive mobile apps.
Though the Jive mobile version (open Jive on your mobile browser) do have the option to add or edit the user profile and avatar when using an Ipad, not when using an Iphone. But because of an issue with 'crop your image' (you can't crop, scroll down or click through) on the mobile version, still the profile / avatar picture can't be uploaded or changed. This looks like a bug. Ryan Rutan can you take a look at this please?
When this croping issue has been solved it should work on the mobile version using the Ipad. You could use the following workaround to provide your users also uploading and changing their profile/avatar picture using an Iphone or Jive apps:
Mobile version using an Iphone
Using the Jive mobile version an administrator can create the settings of the mobile homepage.
You can add a text or image link to the edit profile section, using the link 'https://[your community url].com/edit-profile!input.jspa?
When users click on this link the profile section opens and they can upload a profile / avatar picture.
Using Jive mobile apps
Create a document with instruction how to change your profile/avatar picture using Jive mobile apps.
In this document you can add a text or image link to the edit profile section, using the link 'https://[your community url].com/edit-profile!input.jspa?
Users can search for this instruction and when they click on the link the profile section opens and they can upload a profile / avatar picture.
Hope this helps you moving forward on this.
Thanks for the feedback Michiel.
This sounds like a product bug that needs to be addressed in your customer support group. If you file a case referencing your message here ...they can create the ticket to track it. Libby Taylor is there any other community recourse besides what I've recommended...just wanted to double check =)