heh, I wish it was that simple
Fair enough

Not sure whether there is a straight converter for that format.
However, after looking at "PDS File Format"
http://www.fileformat.info/format/pds/egff.htmhttp://www.fileformat.info/format/pds/egff.htm#PDS-DMYID.3and some python code at
https://github.com/planetarypy/planetaryimageI took the example download 0600R.IMG and 0600R.LBL at
http://www.fileformat.info/format/pds/sample/index.htmand after some python foo, get a .PNG out. A bit messy and not entirely correct, but there is an image

While I realize that you are looking for an easier conversion, here is what I did in case it helps
First, combine files
cat 0600R.LBL 0600R.IMG > 0600R_2.IMG
as when I read the 0600R.IMG only it gives me an error.
Second,
python3
import matplotlib.pyplot as plt
import matplotlib.image as plt2
from planetaryimage import PDS3Image
image = PDS3Image.open('0600R_2.IMG')
plt2.imsave('picture.png', image.image)
and I can see a planetary shape.
I hope you can find a easier solution. Please keep us posted.