The ffmpeg
utility "is a universal media converter." That means we can use it
to convert, for instance, a JPEG file to a PNG file.
There is not a lot to a conversion like this. We use -i
to specify the
existing input file (a JPEG) and then the other argument is the name and
extension of the output file.
$ ls
profile.jpg
$ ffmpeg -i profile.jpg profile.png
$ ls
profile.jpg profile.png
See man ffmpeg
for more details.