Some areas of your web pages may have images that have to be sized a certain way. A good example of this is your Slideshow. If you have a wide slideshow and you load a tall image into it, the content below the slideshow will jump up and down as it cycles through the image with different heights.
To avoid this, and similar mismatches in sizing, you can crop your images down to exactly the dimensions needed for the area they are going into.
To start, find the size you need by right-clicking on the original image you will be replacing, and Save Image As to your computer. Once it's saved, look at the image's dimensions in pixels and write that number down. We'll be referring to those numbers later on.
Here is a short video demonstrating how to resize and crop images as needed in the free web-based image editing program, Pixlr (pics-el-ur).