Thumbnails do not display unless right clicked and 'viewed'

OK got CK FINDER working with CK Editor, can upload files fine and move them round in folders, fine, just cannot see the preview thumbnails?

Additonal to this, I have noticed, that thumbnails are not being created. I can view the uploaded image if I right click and 'view', and it inserts into the CK editor text box fine, but the thumbnail is not being created