GIMP Portable is the popular the GIMP for Windows image editor packaged as a portable app, so you can take your images with you and do your editing on the go. You can place it on your USB flash drive, iPod, portable hard drive or a CD and use it on any computer, without leaving any personal information behind.
This package needs no installation and contains only Open Source (= free full version, no Spyware or Adware).
The GIMP (GNU Image Manipulation Program) is a freely distributed program for such tasks as photo retouching, image composition and image authoring. It has many capabilities. It can be used as a simple paint program, an expert quality photo retouching program, an online batch processing system, a mass production image renderer, an image format converter, etc.