I've just had a look and couldn't see any differences ... but I remembered that I could previously so have investigated further.
On my desktop PC running XPSP3 & Firefox 12 or Chrome the small & large images on WPF and the ones on DPR all look the same but...
On my laptop running W7 & Firefox 12 the large WFP & DPR images look the same as each other, albeit if anything oversaturated in my view, but the small WFP image looks LESS saturated... and better for it
Using IE9 on my laptop all 3 version look the same as each other and same as the smaller WPF version viewed in FF - ie the less saturated version
Not sure if that helps Harry - I see you are using W7 - what OS is anyone else using