Were you actually trying to import those images into VTFEdit as frames in an animated texture? If so, then yes. Or a TGA. I hope you saved them in some non-destructive format that lets you open them back up in whatever you used to make them, or that transparency level is gone forever.
On a related note, this thread inspired me to open up the files for Portal 2's actual fizzler to see how hard it would be to use the base textures to make a simplified material that could at least animate or something and... dear lord what am I looking at. I'll be lucky if I can even turn them into something that doesn't animate, that'll work in SFM posters.
On a related note, this thread inspired me to open up the files for Portal 2's actual fizzler to see how hard it would be to use the base textures to make a simplified material that could at least animate or something and... dear lord what am I looking at. I'll be lucky if I can even turn them into something that doesn't animate, that'll work in SFM posters.