When I use Helium to rip a CD, I generally try to make sure the correct cover art is there before ripping. However, after the CD is ripped, the cover art is getting lost. I go to the album in my collection and the cover art that I added before the rip is not there and I have to add it again.
We found a bug related to this. We have now corrected it and the correction will be in our next release of Helium.
Thanks for reporting this!