I tend to use tinypic but any photo hosting site will work.
I would advise getting more than adequate lighting for your shop, and ideally lighting with the highest color rendering index you can find or just work outside on a clear day. It'll make colors appear more distinct from one another, which should help chasing a ring. The early and latewood will be different textures, in the process of getting to that ring you want, feel them in your hands and your scraper as you scrape down to the one you want.
Maybe try working with the thickest ringed osage you can obtain. Chasing a thick ring will be easier than chasing a thin one any way you look at it. If not confident with your job on it, back it with something like bamboo, hickory, white oak, rawhide/sinew if you live somewhere fairly dry. A self bow is nice, but I would rather end up with a nice laminated/composite bow than a broken self bow any day of the week.