Best Answer Rider of Rohan, 27 October 2016 - 05:37 AM
Alright I'm going to try to explain how to do this via Photoshop, hopefully it can be done in a similar fashion in GIMP.
(You can enlarge the pictures by clicking on them or opening them in a new tab)
Open a blank 64x64 size template and place your icon with the background ready, if you've already merged the layers together and just import that as a new layer that's fine as well.
Now head to your Channels tab
Since this is a fresh picture an Alpha channel is non existent, so we have to create one, in Photoshop it's just making a new layer in the channels tab. (Everything in Red is alpha, so at the moment the whole thing is covered in alpha).
Now be sure the alpha layer is selected and I erase the alpha parts covering Isildur's main body, since this is what we want to see in game.
Once that's done,it's time to export. These are the export settings for DDS and TGA that I use to retain Alpha information for buttons.
Now windows lets me know that there is an active alpha channel immediately by hiding the sky, and when I open the button in a dds viewer the background itself is also still there. So this is how the icon would show up in game both at the on field selection and purchase selection ui.
Hopefully this helps, normally I'd do a better job on the icon and it's channel but this is just for demonstration anyway.