To insert an image in a tutorial, click on the position where you want the image to appear. If you want the image to replace an existing slide, select the “Load image file” button

on the left of your toolbar and upload an image from your files.

If you want the image to stand between two steps, first use the “Add Step” function at the top left corner. This adds an empty slide to the existing ones.

Then upload the image as described above.