Coupon image

hi,
i want show unique image of a product with different (code/barcode) only when user buy that product.

In simple term if user buy product i will show him an image or coupon with different code on it .

Any help is appreciated.
Thanks

Hi,
This can be done by sending an email with the attached image to the customers.
I am having the same kind of problem but I want to send printable E-vouchers which can be downloaded by the customers on their email.
And This should be automatic not manual.I can buy this extension if available.
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