Is it possible to get image size before/without downloading?

[Marc 'BlackJack' Rintsch]

In <1153558311.200477.77950 at i42g2000cwa.googlegroups.com>, aldonnelley
wrote:

> (Oh, and if anyone still has a bright idea about how to get image
> dimensions without downloading, it'd be great to hear!)

Most image formats have some sort of header with the dimensions
information so it's enough to download this header.  Depends on the image
format how much of the file has to be read and how the information is
encoded.

Ciao,
	Marc 'BlackJack' Rintsch