I tried out Image Toolbox for editing images. It’s very feature rich, but very unintuitive to use.
I used this app too, but decided it has too many options and I just want cropping images.
In the grapheneOS Store is this little tool “Markup” which is the original pixel image editor. It doesn’t use any network access and is pretty solid.
Say hello to my Friend Briar:
https://briarproject.org/