Md5 hash of tiles

Hi,

I am trying to figure out best way to update (ie download) only the tiles that have been modified on the server. For the same, I thought if i could match the md5 of the image on server to the md5 of the image that i have at my local server, then i can quite safely decide this.

So i want to ask, do we have the md5 information of the images on the server, or is there any other way to download only the updated tiles.

Thanks
Siddharth Gupta

See the HTTP/1.1 “Last-Modified” and “If-Modified-Since” headers.