I wanted something like GIMP for iOS with which I can stitch together/overlay/crop images, add text, blank out parts, draw on the image, and so on. Nothing in the app store looked appealing, most of what I could find seems to be geared towards photo post processing, so I had the idea of trying Freeform for this, because well, it lets you place various objects on a canvas. And it works pretty well!
Create a new board with the image inside, set it to no rounded corners and no shadow, and then do whatever you want to it with Freeform’s tools.
Then, when you’re done, select Export to PDF and convert it to an image. You can use this share sheet shortcut which I made which makes an image out of it and also cuts away the white frame it generates around the PDF: https://www.icloud.com/shortcuts/fa5e2386588742b2a1f5d41401f2238e
There you go, straight forward basic image editing with a free stock app.
It unfortunately doesn’t preserve the original resolution of the image but it’s definitely good enough for me.