PMC Editing Wiki: Tools GIMP, see also GIMP: Alpha Channel.
2022-04-11T01:43:00Z
Open up a the original image
Select the background color
Invert the selection
Copy that selection
Close the original file - throwing away all the changes so far except what's in the cut buffer
Open a new image, select transparent background
Paste my image in and merge the layers so it's just one layer. I now have an image with transparency!
Save the image in .PNG format
Resave the image in .TGA ( TARGA ) format. Make sure RLE encoding is off