So far i know tga doesn’t embed alpha like PNG. You can add alpha ‘channel’ along with the file.
Here’s the step.
1. Make a selection your logo (make sure you have the running ants around your logo) (it doesn’t matter even if you have background layer)
2. Go to Select > Save Selection
3. Under the Channel option select new (if not selected)
4. give it a name (optional)
5. Click OK, that’ll be saved as a new channel in your channel palette (you can open and see)
now..
6. Save your file and select tga option.
7. Below the save options, check the ‘Alpha Channel’, which will include the new alpha channels which you have created (this option won’t display if you haven’t created the new alpha channel.)
8. Click Save, and check ’32 bits/ pixels’. Do not select the lower bits, it doesn’t work.
9. Done.
10. Open your file again (or drag and drop), open the channel palette you can see your saved alpha channel.
11. Load the alpha from Select > Load selection
12. Click your alpha name and click load and extract your image.
Iam not sure if there’s any other method. Let me know.
If you are interested you can check my photoshop tutorial series (currently adding more) in my blog (https://www.beekeepersblog.com)
Thanks,
Beekeeper