Why didn’t they use screen grabs from the color episodes?
BBC Worldwide Americas must meet for Warner’s manufacturing schedule regarding the packaging came earlier than when the finished DVD assets were made available to them from the UK, so they used the real photos that they did have on hand, which were all black-and-white. A very similar thing happened on the VHS release of this story, only in that instance, the caption on the back of the box actually read “black and white” as well, when it should have said color.