From the Model Mayhem FAQ:

How to I toggle Worksafe mode?
To block Mature images from view, you will want Worksafe mode "On." This is what having Worksafe mode "On" looks like:



When Worksafe mode is "On" images that are marked Mature will appear like this in portfolios:



If you would like to see Mature images, you will need to turn Worksafe mode "Off." This is what having Worksafe mode "Off" looks like.