Add expire header for images stored in amazon s3

Hello everyone Good Morning,

I done adding expire header by put the following code into my product

:s3_headers => { 'Cache-Control' => 'max-age=315576000', 'Expires' 

10.years.from_now.httpdate },

But its work only while i add new product and image.
Already i have 100 of products and images. How can i add expire header
for those which already exist products.

Please advice.

Saravanan P