XnView MP - XnView is a free software that allows you to view, resize and edit your images. It supports more than 500 different formats!
Pixlr - Pixlr® makes it easy to transform everyday images into stunning works of art.
JPEGView - JPEGView is a small and fast viewer/editor for JPEG, BMP, PNG, GIF and TIFF images.
Photoscape - high quality photo editing software, that enables you to fix and enhance photos.
IrfanView - IrfanView ... one of the most popular viewers worldwide.
Adobe Photoshop Express - Easily edit and share your photos in no time!