Half-turns a key, entering to get the pictures (6)
I believe the answer is:
images
'the pictures' is the definition.
('image' can be a synonym of 'picture')
'half-turns a key entering' is the wordplay.
'half' becomes 'semi' (I've seen this before).
'turns' is a reversal indicator.
'key' becomes 'g' (musical key).
'entering' indicates putting letters inside.
'semi' in reverse letter order is 'imes'.
'a'+'g'='ag'
'imes' enclosing 'ag' is 'IMAGES'.
'to get' is the link.
(Other definitions for images that I've seen before include "Pictures; metaphors" , "Mental representations or figures" , "Pictures, representations" , "Semblances" , "These doubles could be spitting" .)