I'm not sure the Annual was printed in full colour throughout -- GW publications at that time were often b/w with Full Colour sections in the middle, including the Mordheim Rulebook, actually. & a lot of the Annual was taken from Town Cryer after it became a b/w magazine (only the covers were in colour).
Certainly I've never come across a colour scan of the Annual -- or a scan of the colour pages of the Empire in Flames book, for that matter. Fortunately, the articles in the Annual that were originally in colour (from the first six Town Cryers, in White Dwarf) are available in the PDFs of those issues.