Yes.
Its called google.com
But seriously, search on google images and do the advance search and it gives you the option to filter by image size.
Ive found images as that I was able to print as large as ~6 feet long.
Its not particularly easy to find massive stuff like that but you can find plenty of high res stuff to save.
For example, I printed a copy of this out (at least I think I did)
13k pixels x 6k
This post was edited by AXIS on Aug 19 2013 09:07pm