Here is a good tutorial on it!
http://www.hiveworkshop.com/forums/miscellaneous-tutorials-456/how-add-screenshot-your-map-description-241054/
Usually people will add the screenshots to their album (don't forget to make the album public, or else users won't be able to see them!). Then you just get the links to the images in those tabs, and put them in
tags. To get the links from images in your album, you can just right-click and "Copy Image URL" (if you have chrome). If you have a different browser, it should be something similar to that. Let me know if you need more info!
Also, usually people will use the forums to "test" how their layout looks. The resource sections don't have a "preview" feature. To "preview" how it would look, you can usually just go to the forums and click "add reply", mess around with your layout, and preview there. When you are finished, just copy that over to the maps section description.