Now you are talking about something I know something about. I have
written the image search software that pretty much has 90% of the
US intelligence market. There are two things you need:

1. Satellite tasking over the area.
2. Enough dedicated eyeballs watching the monitors who know
what to look for.

Believe me, even the commercial satellites such as Digital Globe
have enough information (time / location) and if DG wanted to
collect imagery, they probably could over a weeks time do it.
However, whose going to pay them? Satellite time costs money.
It's not just a bunch of data sitting in a google earth like
database of the entire world. Things are collected as there
is a demand.