Goldfinches

This morning I saw a Great Spotted Woodpecker on the nut feeder so I decided to put out some extra nuts in the hope that I might see the pair and their Juveniles, which usually visit at this time; I have not seen any Woodpeckers since.
 
However, while in the conservatory I saw these two Goldfinches on one of our seed feeders.  There used to be a lot of these in our garden, but until recently, when I saw one, they seemed to have disappeared. Hopefully this is the start of their return to the garden. I am not sure why the picture is this strange green colour.