Gimp User Filter is a work-alike to Adobe's Filter Factory. It is a generic image processing plug-in that can be used to create new filters for The GIMP without having to go through the process of learning about The GIMP's SDK. Many freely available filters that have been created for Filter Factory can also be used with this plug-in.
Image matting tool cuts out objects in photos using an alpha-matting technique. While clear cuts can be found for all objects that are clearly separated from their environment, objects with fuzzy borders and semi-transparent areas don't have a clear outline. The tool creates an alpha channel that defines the degree to which the background shines through the foreground for every pixel. The background color can then be subtracted. The user defines a rough boundary of an object with a large brush and a high-quality segmentation is generated. Problematic areas can be edited manually.
Arachne is program that implements Avidan and Shamir's seam carving technique for content-aware image resizing. It allows realtime, fluid image resizing using this fascinating technique. Seam carving works by removing the "boring bits" from an image, so it can change the aspect ratio of many images without changing the shape of the objects inside.
ArahPaint4 is a textile-oriented paint program, mainly for jacquard. It is a simple paint program for raster palette images. It has good tools for drawing images in repetition, support for handling palette images (color reduction, substitution, protected, transparent colors), contour tools, layer support, unlimited undo/redo, support for drawing in aspect ratio (pixels need not be square), a two level grid, and a coordinates display. It is simple, stable, fast, and works well on large images (>8000x8000).
symTone is a dual cursor image manipulation program that allows users to easily and intuitively edit their digital photos using two mice and two cursors. symTone requires that the user plug in two extra three-button USB mice (in addition to their laptop touchpad or their desktop mouse). Mice with a scroll wheel as the middle mouse button will work fine. Only the PNG file format is currently supported.