Screenshots let people get a feel for your work, and is the most important part of a node. They should be the correct size, and have no heads up display elements. Refer to the User's Guide for information on how to fix this.
If this is a map, it could mean a problem with the lighting, texturing, geometry, or layout; try the Cube Wiki for tips on using the engine. Should it be some other form of content, then it may need to be elaborated upon to be worth something.