I need to collect a random set of images from /b/, including both post images and comment images. what's the best way to collect a completely random sample?

i thought about collecting every image on the catalog, but /b/ deletes every post once it gets bumped out of the 10th catalog page, so i would have to open 150 tabs, and go through all of them one by one.

can't just save all images from the most recently bumped post, then refresh, b/c the most recently bumped post is biased towards porn