OK.
Fresh and ready.
The installation of DXTBmp is fairly simple. Extract and run the program. Once its open, click on FILE and select "Load Extended Image".
Navigate to the FS2002 aircraft folder of the texture you want to edit. For example, in the stock 777 texture folder, there are four *.bmp files:
B777_300_C (cockpit textures)
b777_300_L (nightmap)
b777_300_T (textures)
Boeing_777_Panel_Decals
The nightmap and cockpit textures are unimportant right now, but you may want to change the nightmap at a later time if you find it doesn't match the regular textures. The one to edit is b777_300_T. If your aircraft doesn't have a texture with the suffix _T, then open a few to find the right one. If there are multiple textures that need to be edited, open one of them and continue.
The image will come up in a few seconds with the actual textures in the large window and the reflective map (alpha channel) in the upper-right corner. The alpha channel is what makes the aircraft reflect light like a real one would. The lighter the shade of gray, the less the reflection. IE--white is no reflection and black is mirrorlike reflection. This can be changed, but that will be after we finish converting.
There are two things you can do at this point. The first is save the image in 24-bit format or convert directly to an image editor and then convert straight back again. For this, we will convert straight to an image editor.
On the right-hand side, just below the alpha channel, there is a small button. Click on this and then navigate to the location of your preferred image editor. This can be any editor that will work with *.bmp files (like MS Paint), but I recommend an editor with the ability to use layers. With your editor selected you can now edit the image. Go to IMAGE in the top menu bar and select "Send to Editor" and your editor you selected will open the textures displayed in the main window of DXTBmp. Leave DXTBmp open and running, as you will need it later.
Now edit the image however you wish. I'm not going to go into a repainting tutorial, because it would take too damn long . . .
After you edit the image, click "Save" and then return to DXTBmp.
Click on IMAGE and then "Reload After Edit". This will adjust the image to what you edited it to. If you need to change the alpha channel, you can do it at this time by clicking ALPHA and then "Send Alpha to Editor". Edit the alpha as you wish and then save and ALPHA-->Refresh Alpha. You are now ready to save.
Click on FILE-->Save Extended Image. This next part is very important: SAVE THE IMAGE WITH THE SAME NAME AS THE ORIGINAL! If you don't, it will not work! Save the file in a new folder titled "texture.x", where X is any name you want it to be. At this point you should go back and see if there are any textures that you should edit besides the one you have already done. If not, you are ready to add the textures to the aircraft.cfg. If you don't already know how, I can continue this "tutorial" later.
I hope this isn't too hard to understand, but if you need visuals I can do them tomorrow.
Later all!