Designing question dialogs
When you select from the 'Build' menu the 'Design questions' command, you get this dialog:

When the dialog is completed as shown, the 'Run' menu's 'Consult' command displays the window shown here. This example comes from the file 'Diagnosis_rules.imo' which you will find in the 'Examples' folder.
For as many of your model's questions as you wish, fill the dialog with information to be displayed when the question is asked. 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.
After you've made a dialog for a question, you ought not to change the text of the question in the original model or the dialog settings will be lost. Instead, edit the field in the dialog that specifies 'alternative' text.