Customer Self Service - no pictures

In the customer Self Service website, two pictures are not shown. The picture to put a product in the basket and to remove a product from the basket. Axapta shows the “action url” (what should happen when you click on the picture) instead of the picture itself. In the source of the webpage, no code is there to show the picture. Somehow Axapta does not produce the code to make the picture show on the page. Other pictures are shown, like the “powered by Damgaard Axapta” etc. Anybody an idea what could cause this problem?