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

[aldonnelley at gmail.com]

Thanks Josiah

I thought as much... Still, it'll help me immensely to cut the
downloads from a page to only those that are within a file-size range,
even if this gets me some images that are out-of-spec dimensionally.

Cheers, Al.

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

Josiah Manson wrote:
> In the head of an HTTP response, most servers will specify a
> Content-Length that is the number of bytes in the body of the response.
> Normally, when using the GET method, the header is returned with the
> body following. It is possible to make a HEAD request to the server
> that will only return header information that will hopefully tell you
> the file size.
>
> If you want to know the actual dimensions of the image, I don't know of
> anything in HTTP that will tell you. You will probably just have to
> download the image to find that out. Relevant HTTP specs below if you
> care.
>
> http://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html
> http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
>
> The above is true regardless of language. In python it appears there an
> httplib module. I would call request using the method head.
>
> http://docs.python.org/lib/httpconnection-objects.html
>
> aldonnelley at gmail.com wrote:
> > Hi there: a bit of a left-field question, I think.
> > I'm writing a program that analyses image files downloaded with a basic
> > crawler, and it's slow, mainly because I only want to analyse files
> > within a certain size range, and I'm having to download all the files
> > on the page, open them, get their size, and then only analyse the ones
> > that are in that size range.
> > Is there a way (in python, of course!) to get the size of images before
> > or without downloading them? I've checked around, and I can't seem to
> > find anything promising...
> > 
> > Anybody got any clues?
> > 
> > Cheers, Al.