So I downloaded the plugin from NVIDIA and installed it, but when I open the skin I want to edit, I get this: I would use GIMP 2.0 as it opens fine in there but I cant use GIMP atall, i've used photoshop for so long its weird, I have seen some people on here saying they use photoshop to edit skins, I dont see how because this is all I get, if someone could direct me in the right direction that would be great.
Yeah, it doesn't really work for me either (using CS6). So what I do is to open the .dds in Paint.NET and save it as a PNG, open it in Photoshop to edit it, I then save it as a PNG again, open that up in Paint.NET and save it as a .dds. If GIMP can also open and save as a .dds, you could obviously use it instead of Pain.NET.
I was having the same problem as well. I searched forever until I came across this older version of the DDS plugin that works for CS6. I can't remember where I found it, but it works. As always, use your virus scanner to scan it just in case. I've scanned before and found no problems. You have to create a "File Formats" folder in your plugin folder to place the DDS file in.
Sometimes the "Channels" aren't all ticked (Colour channels) which makes seeing the skins impossible. I had the same problem. (I use Nvidia plugin by the way.)
Uncheck Load Mipmaps. Mipmaps are basically LOD textures which is why it starts from the original size and it keeps halving until it's only 1px wide.