According to the 2005 Sky documentary this is an Essex Police photo.
Why the blood appears wet is anyone's guess. However if it was at all conclusive Jeremy would be released by now. But he is not thus the photo is inconclusive
They are all Essex police photographs, however this particular image in its current form originated whilst GDS was representing JB.
The colour of the image has been altered to increase the warmth, i.e. the reds are more pronounced. The blood appear a more vivid red; Sheilas skin is 'pinker' than it should be; the rifle is more saturated and is 'blacker' than it should be.
The blood appears wet in that image because it has been altered digitally so that it appears that way. It is actually exactly the same photograph as the cracked blood image. Bridget and I cropped the images and placed then side by side, I will see if I can retrieve that post.