Loading an image and making it into a link
The link url tells WordPress what to do when people click on the image.
• Normally click “None” which puts no URL in the link field so nothing will happen if people click on the image.
• If your image is big—a flowchart, for instance—and you want a small image in the page which is a link to the full size image (which will open in another window), click “file URL“. Choose the size of the image you want to put into the page—thumbnail, medium or large—and click the radio button. (I have set “large” to fill the width of the column: 500 pixels.)
• Don’t ever use “Post URL“—it opens the image in an ugly window!
• If you want to use the image as a link to another page, type its full URL in the link URL field.