I had a 25 % Discount on an image for 24 hours. After I deleted the 25 in the editing area of the image I still have those scratched numbers. They are showing the right (unreduced prices) but they are still there:

http://www.flashstockphoto.com/image/sensual-closeup-portrait-of-beautiful-young-woman/?r=http://www.flashstockphoto.com

Leo, can you tell me how I can get rid of them?

It looks like if you leave the discount field blank, then you will end up with your situation (with no discount but scratched out prices).

Try putting a 0 in the discount.  That should fix it.

This idea could have come to my mind too 
Thanks it's fixed!
A bug in my brain not in the theme