- Unshake is a free photo editing software written in Java that can remove blurs from your photos. It can be used on virtually any platform (Linux, PC, Mac, etc.)
- GIMP is the GNU/Linux-based photo editing software. It also exists in versions for Windows, Mac OS X. Since it has a full system of plug-ins, you can go quite far (including improving your photos with the Refocus-It and Iterative Refocus plug-ins for sharpening the photos).
- Another specific noise-reduction plug-in for GIMP is the GREYCstoration plugin (it will work well to improve photographs shot at high ISO levels).
That’s worth trying, isn’t it?
Besides, an for those of you who are strictly interested in using GIMP, there are additional resources to check: