1. Link to an image on the web. Simply go to insert, then insert image, and you will be prompted to enter a url for an image. Feel free to change the dimensions in any way. This option is great if your network blocks imgur.
2. Upload an image from your hard drive. Click on the upload image button and you will be able to add any image from your hard drive. Please note that the image will be uploaded to the image hosting site imgur. If your network blocks imgur, you will not be able to view the hosted images.