As of 3.1 there is a stone age 10MB limit on graphic layers in a map. ArcMap did not have this. If you want to insert more than 10MB of graphics, like picture markers for example, into the map the only way is to make a style file, make a feature layer, compose a marker symbol of each graphic needed, and assign the right marker to each symbol. A tedious and pointless process that greatly slows down workflows. This is an equivalency issue.