...ok I know I always recommend dokuwiki for everything but it is super easy to set up and doesn't need a database or anything and it comes stock with a nice gui media manager and a lot of plugins that extend that functionality.

If you are willing to provide or pay for the hosting of a large amount of images I don't see the reason to go with anything more complicated though you may find something more minimal that suits your needs.

https://www.dokuwiki.org/dokuwiki

https://www.dokuwiki.org/tips:cms

I don't know if there is a way to handle metadata for non-jpg images but there are a number of ways you could organize gifs including photo namespaces.

https://www.dokuwiki.org/media_manager

or using the imagebox plugin and just directly put tags in the caption

https://www.dokuwiki.org/plugin:imagebox

or a number of other ways probably.

The nice thing about this solution is all the data is accessible and in plain text readable markdown which also makes it easy to strap other things onto, search through with whatever tools you want and easily run a backup process on (especially since everything is neatly contained within a folder).

Don't make the mistake most people of thinking dokuwiki is only useful as a traditional wiki, it is such a simple and general tool that its power extends far past that.