There are two ways to add images to your diagrams.
One is simply drag an image onto a diagram. Then check [Insert the image file.] and click [OK].
Another way is to cick [Add an image] button on the diagram tool bar and choose an image file you want to add.
Mini Icons are pre-installd icons that you can add to model to add an extra expression to it.
Add Mini Icon to a model
Select a model on the diagram and choose an icon from the tool bar.