IrfanView is an incredibly useful program for modders!
It can view a huge variety of image files, including dds if you get the plugins
download for it as well (also free). Plus, it can do some decent recolors of textures...

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Click on the two small pics to the left to see some examples
of what I've made with just IrfanView.

The body textures of the Mushroom Sprite, and the Blood Waterfalls
were modified with Irfanview's Swap-Color and Enhance-Color features.