Bright is a tool that converts 24 bit bmps (16 million colours) down to 8 bit (256 colours). Your graphics program can do this, but Bright does a much better job of it. This is necessary because AH can only see 256 colour bmps. They take up a lot less video memory. I'm guessing your skins are not 256 colour and that's why nothing is working.
To use Bright, move your skin's bmp to the Bright folder and double click on bright batch file. You should see an MS DOS window open as it runs through the process. Once it is done move the bmp file back to your skin folder. I put a shortcut to the Bright folder in each skin folder and another shortcut to any skin I'm working on in the Bright folder.
To use the skin viewer, select the plane you want in the top drop down box. The lower drop down box should have the individual skins of that type in it i.e. spit8_2, spit8_3 etc. Select one and it should appear.