I can't find anything about RLE Compression in Photoshop. How do you turn it on/off?
edit by tirpider: tagged title
It's an annoying one I have it off by default but sometimes I'm sure it does it anyway.
When saving a texture do not simply "Save", select "Save As", after which a dialog box will appear with resolution options (always make sure it's 32 bits if using an alpha channel) and ensure the "Compress (RLE)" is unchecked.