HundThere's a fresh and very promising open source alternative to Instagram that's called @pixelfed. It's not only decentralized but it's also federated via ActivityPub. :)
Jonkman Microblog is a social network, courtesy of SOBAC Microcomputer Services. It runs on GNU social, version 1.2.0-beta5, available under the GNU Affero General Public License.
All Jonkman Microblog content and data are available under the Creative Commons Attribution 3.0 license.