Look into and check if models in GMG are in line with OStatus objects and activity entries. Create necessary models.

This will probably need discussion on what to include in the first around and what to exclude. First round should at least contain Image and Comment objects, as well as the post verb.

Add signal functions or something similar to create entries when a user posts a new Image or a Comment or access activity information by some other means (depends on the implementation). Keep in mind that GMG must be able to support other verbs (e.g. favorite, follow) so reading directly from MediaEntry model is probably not the optimal solution.

Create a pure atom feed from user activity entry feeds, i.e. do not show specific OStatus/Activity Stream elements. Title, summary, published, id and author is enough to work with to begin with.

Comply to the Atom standard and create and extensible feed framework which is ready for the Activity Stream extensions.

Make the feed discoverable from the user profile page.

Incorporate activity stream namespace and represent objects and verbs in the stream according to the Activity Stream base schema. If Atom feed and the feed framework, as well as the model structure were created with extensions in mind, this shouldn't be difficult.