@Triffen @GIMP Not yet:

> Bruno Lopes has truly taken the lead to improve our build and packaging process on multiple platforms.
>
> Over the summer, he created an experimental AppImage build (as detailed in a prior news post). If you are interested in improving it further and hopefully making it available as a standard download, please get in touch! Bruno has also created flatpak build scripts to make the process of creating your own GIMP flatpak much easier.

It's not there yet since there are many things (continued from my quote) Bruno is tackling with AppImage being just one and this work isn't completely done yet, but can continue til release.