You got me confused there a bit, since it's been a while that I used my own tool.
1. Go and download:
https://github.com/Sasabmeg/FEV/blob/master/release/FEV_v1.3_exportfix2.jar2. Use jarfix to fix the autolaunch of jar files if you havent.
3. Double click FEV_v1.3_exportfix2.jar
4. Select file. (I used fallout.dat\art\scenery\tree11.frm)
5. Exp single frame
5.1 Before prev, make sure you did NOT select the checkbox "Image background"
6. Save the file where you want as .png format.
7. Use Infranview or Paint.NET or whatever editor/viewer you use that can handle transparency.
8. Get the following image in Paint.NET.
PS: I do not check this site daily, or rather have status open and I do not realize there are new posts. If something is urgent, or you feel like failing hard, you can contact me on discord.