Designing a startup dialog
When you select from the 'Build' menu the 'Design startup' command, you get a dialog like this:

When the dialog is completed as shown, the 'Run' menu's 'Consult' command displays the window shown here. This example comes from the file 'Feline Dtree.imo' which you will find in the 'Examples' folder.
Fill the dialog with information to get the display that you want for your model's startup. If you choose to add one of your own picture files, be sure it is a JPEG (*.jpg) file or a file in some other format that is understood by InterModeller.
The 'Preview' button is handy to let you see how the result will look while trying out the 'Scale picture' option and other settings.