...or have an other solution. (Especially one that will work with Lightening when we switch.)
We use the image formula field on all Product records, in list views and to view on iPhone Ap.
This is what my currently formula field looks like. It squashes all images into a square.
IF( ISBLANK( Thumbnail_Document_ID__c ) , '' , IMAGE("/servlet/servlet.FileDownload?file="+Thumbnail_Document_ID__c, "No Image",220,220))
