Basically what you are looking at with your images is reducing the quality. Now in a template setting you can get away with dropping them more then you could for an individual picture or graphic. Reason for this is it was meant to be looked at as part of a larger picture and not stand alone. The chances of someone pulling that image up just to look at is slim. And the chances of them enlarging the image is even slimmer. You said you where saving the quality at 12. I would drop that back to around 8-9 and see where the distortion of the image starts to happen then bump it up one level higher. Even if you end up saving your images at 10. The size reduction is around 30% normally. In the end this reduction will help with the load time of your site.

__________________