Editing alpha channel to your image. Alpha channel is the transparent part of your image which for example OFP and ArmA uses for transparency like in vegetation or vehicle window textures.

Editing alpha channel in PaintShop Pro by Gnat

1 - open the image in a PaintShop Pro
2 - save as uncompressed 24bit TGA file
3 - use magic wand to select the background only as mask
4 - invert the mask
5 - select “save mask to alpha”
6 - save TGA again
7 - done

EDIT: Note: TGA file must be save as 24bit (with alpha channel) and UNCOMPRESSED

Editing alpha channel in Photoshop

You make logo normaly when you finish painting select all places what you want to be transparency an from menu selections choose invert and from the same menu choose save to alpha channel save and it is all. Now save file as 24 bit uncompresed tga.

Paint all that you want transparant a color like gray or that differs from your texture completely. That way its real easy to select the area that you want tansparant using the “Magic Wand” And continue on with the method stated above.