I think what some people are suggesting is that the police deliberately made available poor quality copies to disguise the fact that Sheila had cuts and abrasions on her arms and also to disguise the fact that the blood trails were still wet when the pictures were taken.
It is worth considering the question why after such a long time were Bamber's defence given the negatives in 2011. One possible reason is that the CCRC had rejected the testimony of Meloni and Cavalli in relation to the one high resolution photograph of Sheila the Defence had obtained, so the thinking may have been:
"We can let them have as many photographs showing wet blood as they want. Since we have rejected that evidence they can't use the same argument again."
But they may have miscalculated. They may have overlooked the fact that the good quality photos the defence now have can prove that Sheila has cuts and abrasions and that is a separate point. They are relying on technicalites to reject evidence, but they may have slipped up.
This opinion most closely represents my own opinion on this. I think the truth may be a little more complex - but you have the gist of it.
I don't think Bird (and/or whoever else took pictures) were fully competent when discharging their duties as crime scene photographer/s on the day.
I agree regarding the concept of 'keeping Bamber in on a technicality' - which is the exact opposite of what is often suggested.
I also think the negatives were released and sent to lab at a time when Simon McKay was fully committed to concentrating on the silencer evidence. The defence then had to face the blow of demands for further experiments and reports which they could not fund (and the resulting failed judicial review).
There was also the small matter of four million pages of unindexed unreferenced documents released to the defence, totally jumbled up (probably a deliberate act).
Regardless of any potential legal wranglings and technicalities - I'm not sure that the significance of the wounds is 'sinking in' for some members on the forum. The significance is huge:
Some cuts are completely independent of any other blood in their locality. Therefore such cuts
cannot be 'trails' or 'runs' or 'smears' - since they have no source of blood other than the cut itself.
Some members have painted themselves in to a corner with their stance - in several instances, a changed one. I think they are really struggling to come to terms with the implications of Sheila having wounds.