I was gonna answer if you extract the files, they show up in the folder where you opened the file in .tga format. But thats for Gigapack. Just looked at triangulatortrees, and it extracts the frames in .wlr format. I have no idea what this format is. ( Truevision? )
I doubt simply renaming the extension to .tga or .bmp will work.
If i got it right, what triangulator does is this : that triangulator not transforms it into a file that the engine can use , engine can use the g17 files aswell , but what does the triangulator do , is that it brakes the units into small triangles so that the parts that are the same in several frames are not copied , that way you get alot smaller files, thus able to put more troops.
Also what exactly you want to do with them? Edit them and put them back in CII, or transfer to an other gsc game ( AC,...)?
More questions instead of an answer.
Gonna have to ask around.