Whenever they were released, doesn't really matter, if they showed what is being claimed here, they'd never have seen the light of day but there is no evidence to prove that they were kept from either the defence of the jury.
They could hardly have been shown at trial this close up - if the prosecution's case was that Sheila had no injuries. As somebody in the jury or defence with the same vision as my self, Maggie, Bill, Susan etc would probably have questioned why she had crescent gouges.
I cannot see how bleeding gunshot wounds to the neck/throat can cause crescent shaped blood stains with further bloodstains underneath them in the form of a nail scrape / graze.