http://blog.wolfire.com/2009/02/wolfire-graphic-converter-utility/
One cool feature in Overgrowth is that it automatically and intelligently converts your image files when you run it. For example, Aubrey can be designing a level and working on textures in the raw TGA format. Aubrey likes TGA because it has a separate channel for alpha transparency so in Photoshop you can draw directly onto its transparency mask seamlessly.
However, the TGA format is completely uncompressed and produces huge files which are not really practical for video games. There are many other image formats that are better for production. Aubrey could manually convert everything to a lossless PNG format, for example, but that would be annoying. Why should Aubrey have to deal with that? Luckily, we have some technology.
When a developer launches Overgrowth (or even just alt-tabs into it from Photoshop — see live texture/shader updating) these files are seamlessly converted into the superior PNG format if they need to be lossless, or the extra hot DDS format using DXTC texture compression if appropriate. Right now you tell it whether you want it to be lossless or not by adding _nocompress to its filename.
This was actually really easy to do thanks to FreeImage. As a bonus, we are releasing a little utility based on our FreeImage graphic converter wrapper. :) Feel free to use it to convert your images.
Wolfire Graphic Converter
Mac OS X: http://cdn.wolfire.com/misc/converter-mac.zip
Windows: http://cdn.wolfire.com/misc/converter-win.zip