I would be surprised that the author wasn't using WebM to get a smaller filesize (not to mention higher quality) but the project itself leads me to believe that the author has a lot of free disk space to use
There’s no need to make further assumptions about the author (who btw took the time to build a very useful tool and share to in the Internet for free). Just point out the issue of the GIF and move along.
I think you missed something here; parent wasn't insulting the author. They were inferring that someone who made an archiving tool probably has resources that help with archiving (bandwidth means access to documents and storage space means a place to save them-- you get the idea).