@EllieK
It is possible to make an own account on pixelfeed with your fediverse-account-name. Then you follow with your mastodon-account your pixel-account an then all public photos from pixelfeed come in your timeline of mastodon. So I did it for some time. On pixelfeed you maybe you meet more people who are interesting in your wonderful photos and you can communicate about with them. That could be a reason for pixelfeed and mastodon parallel.