Getting Post images to show up in widget

Hey guys, I am about to start a wordpress project for a client and in planning, they want a widget that displays photos. Similar to something like a flickr widget where its just 8 images or so in the widget displayed in line. nothing too major. The thing I am trying to do though is get the images from the posts.

The client is a fire company and they are going to post pictures of their calls and all of that. Id like the widget to just pull images out of every post and the widget would hold like the the latest 8 or whatever number I decide.

Basically to further explain, the fireman creates a new post, writes up what happened, and inserts a few images into the post. Once they publish the post, Id like the widget to pull images and put them into the widget and then when clicked open a lightbox.

Anyone know how to do this or has anyone done this in the past?

Thanks guys!