here are some basic guide on how to edit DDS file and TGA file..without using photoshop..
1. first u need to back-up ur files..copy the folder or file before you begin editing it.. its for you to easy to bring them back if u are encountered an error while editing.
2. now look for the file u want to edit and look for its size and remember the file name..
3. Put the pictures u want to edit at microsoft paint (if the file cant read at paint, convert it 1st to jpeg)
4. Now resize the image according to the size of the file u want to change..
5. Now save the file as jpeg..then use dds converter to convert on the files u want..example: TGA file or whatsoever..
6. Copy the file on the folder of the file u want to change.. then boom thats all..