I don't think I have a picture of it but I have used a bar roll by using two straps and two short (1.5" long maybe) pieces of PVC pipe as spacers. The strap goes through the pipe, around the bar, around the sleeping bag, and back to the buckle. It held securely and the pvc spacer kept the load away from the bar.

I found it to work just fine and to be a very inexpensive solution compared to fancier bar roll accessories. A $2.49 set of Coughlin's straps and a few inches of 3/4" pvc pipe is a lot cheaper than any of the solutions from Revelate or other bikepacking bag company. Where the fancier solutions might be better is when the load is something that doesn't attach securely with just the straps.