Hello Sinea Pies! Sorry it took me so long to respond but my regular day-job is getting busier with the warmer weather and I am trying to complete the 30/30 Challenge!
To be honest, I have seen a lot of people using so called dividers in their Hub Articles. Some of them really looked great while others were of lesser quality. I am not sure of the total affect but what I can say is that dividers are similar in quality to screen-shots and tend to be pixelated (low-quality image).
My suggestion is that if you can create a quality divider than use it, but if it looks grainy or pixelated then I wouldn't because bad images hurt articles. I am not an expert on this particular question so use my opinion with caution! I suggest that you ask this same question in the Help Forum and see what others have to say about this. I am interested in hearing more about this as well. http://hubpages.com/forum/2
Marisa Wright and homesteadbound make some great points as well. Everything in one Hub article belongs to one URL. Search Engines read in code, not in text and pictures like we do.
I had considered adding Dividers at one point myself and I am not sure if they add value or take away from the Hub credibility. This is a great question and I would love to see more answers from people who have more experience with Dividers. Thanks for asking!