In order to Change properties of a graphic, you must first save the page that they are on. During this process, you will be prompted to save the graphics on that page. This is the time and place you can set the properties for a JPEG, GIF, or PNG (Portable Network Graphic — an alternative to GIF).
To change the properties of a JPEG, GIF, or PNG graphic that has already been saved to the page, you must modify the image somehow — such as rotating it or cropping it — and then resave the page.
The graphic is in JPEG format
Note Some Web browsers do not support progressive passes.
The graphic is in GIF format
Note If the graphic is in the PNG format, you can also change its properties, but this format isn't very common and isn't supported by all browsers.