In order for images to display properly in Content Boxes, Rotators, and Event Boxes, you may need to re-size them. This ensures that the entire image will be seen by the visitor. Some people choose to use advanced photo editing software to accomplish this, but there are also many free options. Below are some websites that can scale and crop your images to fit specific dimensions. 

The Image Manager has a unique Image Editor built in. With this editor you can resize and crop images to fit event boxes, rotators, or content boxes.

http://www.webresizer.com/resizer/ (Simple resizing and cropping, easy to use)

http://drpic.com/ (Offers many more image editing features)

http://www.resizeyourimage.com/ (As basic as it gets) 

http://evernote.com/skitch/ (Download required, easy to annotate and resize images)