Well I must admit you got me a bit confused here. Forum: American Conquest. Title of thread: C 1 to C2 conversion.
So, are you trying to convert units from American Conquest, or from Cossacks 1? And to C2 ( Cossacks II)? Not to Hoae?
Now, you say you have .bmp's ready. Are those extracted from CI/AC? ( with gpviewer?) You do say 'screenshots' right. If it are screenshots indeed then there is indeed no alpha channel present. The BmpToTga tool is specifically custom created for extracted bmp's and their corresponding alphachannel from gpviewer to bind them into a single .tga file with the alpha channel inside in order to save time doing this in photoshop. I have only requested this. It was never created with the intend of making alphachannels for bmp 'screenshots'.
Pls give more information about what unit you are trying to do, or anything additional information you want to do.
If however you do have the alphachannels for the bmp's then both the bmp & alphachannels ( 00001.bmp & a00001.bmp ) should be in the same folder with no other file's in there and then direct the paths in the tool towards that folder and a new output folder. The rest the tool does for you.
Also, is it an unit or icon file you are trying to make, cause you do mention icons. If its a problem that the icons do not loop, you should set directions in options to 1 instead of the default 8 or 9.
Also, if indeed its an icon file, just use an existing icon file ( example the background: upgrade.g17) and paste the bmp's over it. Before I went on vacation i made over 600 icons for all units and buildings in game cause they were not present in the editor. I also couldnt be bothered to make an alphachannel for each icon. I still have to implement them all in the md file's but it works just fine that way.