ScreenshotCleaner is a small application designed, as its name says it, to cleanup screenshots images files.
It can automatically remove unwanted background pixels for rounded corners and add extra transparent pixels all around the image.
The image can be obtained by opening an existing file, or directly retreived from the clipboard.
It is available in english and french, and can easily be translated into other languages.
It can actually be built on Windows using Code::Blocks or Makefile.
It can also be built on Linux and on OS X using Makefiles but there is actually no profile to clean screenshots on these systems (note that on Debian linux, the "Windows 7 Default Aero Theme" profile gives good but non-perfect results).