Image Toolbox★★★★☆An extremely powerful image editor for Android. And not just the usual features like crop, adjust contrast or brightness, maybe apply a filter, but you can do batch edits, format conversion, scaling the actual pixel image, editing metadata…all the things that mobile apps tend to hide behind the curtain. And it can preserve EXIF data when you want it to.
Sly (Image Editor)★★★☆☆Simple, friendly, privacy-respecting image editor for Android and Linux. Convenient for most basic photo adjustments, but metadata handling is currently broken, so I can’t use it to just crop photos for iNaturalist. Once that’s fixed, though…