<p>I've uploaded a bunch of images to Amazon S3, and now want to add a Cache-Control header to them. </p>

<p>Can the header be updated without downloading the entire image? If so, how?</p>

It's beta functionality, but you can specify new meta data when you
copy an object
. Specify the same source and destination for the copy, and this has the effect of just updating the meta data on your object.
```
```
PUT /myObject HTTP/1.1
Host: mybucket.s3.amazonaws.com  
x-amz-copy-source: /mybucket/myObject  
x-amz-metadata-directive: REPLACE  
x-amz-meta-myKey: newValue
```
```