Alt Images with SEOTools?

Hi Everybody, i'm a newbie in SEOTools and I would like to know if it's possible to knom ALT images and images' weight with SEO Tools ?
If yes, what is the code ?
Thank you for your help !

List of all alt tags of all IMGs:

=Dump(XPathOnUrl("http://tessin.se","//img","alt"))

What is image weight? Size on disc? Did you mean width?

Hi Niels,
thank you for your answer !
I would like to know the size (in Ko) of each images of a site, that is what "weight" means for me ! :wink:

Finally, i would like to crawl every pictures of a sites and know every size of each images...