Council just sent me over the first artworks, some technical points:
They need to conform to the current standards of item images, meaning you need to read this:
They probably should be coloured, as a recommendation make the greyscale image alpha transparent, then paint colour over it, using layers and possibly transparency to make it look good.
We want one artwork for each item, only one can be used and only one is going to get the gold coin.
If you cant colour them in, then you need to talk to people who can.