Here are some useful dimensions for resizing images:
How to Crop Images
There are many ways to crop and resize images. The WYSIWYG editor allows us to resize images, but it does not allow us to crop them. Photoshop is our #1 photo editing software, but it can take time to learn and is costly. If you’re looking for a quick and easy way to crop photos, we recommend Pixlr, a browser-based photo editing tool. Visit http://pixlr.com and take a look at the tutorial below to learn more.