For various reasons others have mentioned you can't stop them printing 
multiple copies once they have the image.

So ... make the coupon a little more complex - include a serial number on the 
coupon. It could be something as crude as a counter or as complex as an MD5 
encrypted time reference. There would also be numerous ways to script it with 
server-side scripting if you have access to that.

You couldn't stop forgeries ... but depending on how you integrate the serial 
number that may be easy to detect. Then you would also have to keep track of 
unique coupons returned ...

Good luck,
KathyW.

> I have a question surrounding the printing of online coupons for a site
> I am designing. 

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