I am new to this program and I am wondering if it's possible to deselect the Pictures, Weather and TV buttons so that they do not appear in the main menu because I am not using them?
Yes go into your Media Portal Configuration. Once in it click on plugins. Go ahead and highlight what you don't want and you can do one of two things.
A) click the radio button that says "Disable" and shut them off
B) Click on the "InPlugin" radio button and move them from the main menu into the plugin folder.