What information can I find out about a JPEG given only its URL using Perl?

Can I determine its modify date? File Size?

I notice that most browsers can determine the size of files being downloaded. Do i need to begin a download in order to get this information?

If I were to download the first 500bytes (or so) of the JPEG, what info would this tell me about the image?

I guess my main concern is "has this image changed?" without actually downloading an image referenced by HTTP. If i already "know" the expected file size, or modify date, or details in the jpeg header, what's the minimum that i need to do (/download) to answer "has this image changed?"

thanks :)

In reply to Getting JPEG details without downloading by jasonjohn

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