Moodle makes it easy to attach or insert photos in a forum post or other textbox. We can get into trouble, though, if we post a photo from a cell phone or digital camera without resizing it first. A photo that is more than 3,000 pixels wide in its "native" (original) size will completely blow out a Moodle text box—not a helpful thing to do! Also, photos tend to be space hogs, often taking up more than 1 MB each, and are slow to load and display online. Fortunately, it's not hard to resize photos, even if you don't have special editing software.

These instructions are what you need!