Pixelfed is an image and story app. You can create albums and collections. You can explore hash tags and categories.
Just like Mastodon it’s a network of several interconnected servers. You can join any server and communicate with people on other servers too.
Albin Social is hosting Pixelfed.green.
Recommended mobile apps
There are no mobile apps for pixelfed yet, but it is worked upon by a group of open source developers. Coming soonish.
The Pixelfed project
Project website: pixelfed.org
Source code: github.com/pixelfed/pixelfed/
The first mobile app project: PixelDroid.