GIMP - GIMP is a multiplatform photo manipulation tool.
IrfanView - IrfanView ... one of the most popular viewers worldwide.
Adobe Photoshop - Adobe Photoshop is a webtop application for editing images and photos online.
ImageGlass - You can use Image to view your digital images and photos of many different formats.
Krita - Krita is a professional FREE and open source painting program. It is made by artists that want to seaffordable art tools for everyone. Concept art. texture and matte painters, illustrations and comics.
XnView MP - XnView is a free software that allows you to view, resize and edit your images. It supports more than 500 different formats!