I'm at a loss to understand why anyone would post such a dreadful photo.

http://www.ukclimbing.com/forums/t.php?t=418424
It was posted to illustrate a thread he'd started, not for the sake of showing off his photography skills. The photo section doesn't just exist as an art gallery for photographers to show off their skills :)

It might make me scream trying to set it up in extremis.
5 for effort though.

Luke90, I appreciate what you're saying but naffan has allowed voting and comments on the photo so I'm not out of line in my comment. Also, I've read the thread and I think the photo also fails as an attempt to illustrate the point being made there. It's impossible to tell how the screamer is constructed from the photo and being so out of focus doesn't help. It looks like the kind of tangle you'd get if you put your hand into a rucsac of climbing gear and randomly pulled something out. So, sorry, but still a dreadful photo.

yeah 'aln' i totally agree this is such a terrible photo. But seriously, get a grip mate.

the screamer is maded form lots of alpine butterflys on the blue cord (6mm). the red cord (7mm) is threaded through each butterfly a number of times and pulled so that it twists itself into a very small prussick. on of these isnt strong enough to hold anything but together they are strong. the red and blue cord is attached to the top krab and the red cord is attached by itself to the bottom krab.
the idea is that it will become harder to rip as more force is applied.
1. butterflys seperate, little force required
2. cord pulls through all of the butterflys at once, lots of force is required.
and yes my photography skills are some what lacking