After you've created a product you can also add a product image. You do this by clicking 'Add' in the 'Images' section of the Products menu.
To put that product image on your invoice you'll need to add it to your invoice layout first. Go to the menu 'Settings', click on 'Corporate style' and on the square next to the invoice template.
You can add product images with the key ‘$Line.image$’ from the menu on the right hand side. First put your cursor in the invoice where you want your image to appear and next click on the key. Your product image will now show on all your invoices.
Hint: You can create an extra column in which each line contains a product an product image. Right-click on the blue table and choose 'Add column'. Nog add the key in the extra column.
