Spring RTS Engine

So I have my texture and want to add teamcolor.
Appearently that is done via the alpha channel. Over 9000 years ago I actually managed to make a .dds texture with alpha channel but I can not find the guide in the wiki anymore. I also would like to use .png for texture because I can just open them in ie irfanview and look at them.
I do not want to spend hours learning how to shop da whoop so my question to all the pro shoppas:

What is the easiest way via free software to edit the alpha channel? Tried Gimp, got confussion.
I would like to have my texture and just draw over all areas that should become teamcolor. Or something that takes the texture and combines it with another greyscale texture and the greyscale becomes the alpha channel, that would work too.

DXTBmp, available here.

Look here for more info on using it for spring.

With Gimp:
- Somewhere in the Windows menu, enable the layer window.
- In layer menu, add alpha layer
- In Image menu, mode submenu, split to RGBA..... Ahhhh the option is gone from newer Gimp versions!! I won't be able to do it anymore. I can only hope I kept an older Gimp installer around.

Edit: Wait, I found it back. Now it's in color, component, decompose. Change to RVBA in drop box.

Then you use the layer window you enabled previously to only show (the eye) and only work (the selected) on the alpha channel. You do your stuff here (personnaly I just dump and anchor a greyscale image made with another image editor), then use the menu color, component, again to recompose the image from RVBA.

Of course the pros might squeal that it's not how it ought be done, but meh, works for me.

And does the french "calque" even stand for "layer" in the english version?

You can also use the gimp channels dialog
to control which channels (RGBA), are active,
and which channels are visible. I've never
had a need to decompose an image unless
the decomposed layers were the end product.

DXTbmp sounds exactly like what i wanted :)

https://springrts.com/wiki/Units:Textures

or add here: https://springrts.com/wiki/Gamedev:Main ... _Tutorials or somewhere