GIMP is a free program for such photo retouching, image composition and image authoring. Essentially it's the closest thing to Photoshop you can get for free.
GIMP vs darktable opinions
Both tool have totally different usage purpose. Gimp is a photo editing and digital art tool without any photo management usage.
Darktable is a photo editing tool, GIMP is a retouching tool.
It's a photo editing app, not a gallery/catalog app.
GIMP is not a very good virtual darkroom tool, but it is a good editor and compositing tool.
digiKam is an advanced digital photo management application which makes importing and organizing digital photos a "snap". The photos are organized in albums which can be sorted chronologically, by folder layout or by custom collections.
digiKam vs darktable opinions
digiKam can do simple RAW editing, yes, but it's mostly for organization. The functionality is not the same.
RawTherapee is a free RAW converter and digital photo processing software. All changes can be applied and batch processed at a convenient time.
RawTherapee vs darktable opinions
RawTherapee is way easier and more logical organized than Darktable. I really tried to work with both, but in Darktable elements are structured in a not logical order. While RawTherapee is bit slower in startup and loading pictures though.
Create incredible photos anywhere with all-new Lightroom CC and 1 TB of cloud storage. Get powerful editing features on any device in a new, easy-to-use interface.
Adobe Lightroom vs darktable opinions
Snapseed is a photo enhancement and sharing app with a powerful suite of imaging filters and tools for anyone, anywhere to transform any image into an extraordinary photo.
Snapseed vs darktable opinions
cannot open raw camera files.
Eagle helps you manage pictures, screenshots, user interfaces and designs that make your lightbulb shine. If you are a designer, you will definitely love this!.
ACDSee is a complex, multi-purpose application that serves for viewing, organizing and editing digital photos. Furthermore, images can be shared on social websites or your own space on the developer’s website.
From high-precision light and color tools, to advanced clarity and dehaze settings, to the ability to create and save your own filters. Polarr is the ideal photo editor for bloggers, students, and photo professionals alike.
PhotoFiltre 7 is a complete image retouching program. It allows you to do simple or advanced adjustments to an image and apply a vast range of filters on it. It is simple and intuitive to use, and has an easy learning curve.