From the description on deviantart:

I'm a little late with postcard 4 (this was supposed to be done in February) but I've just had so much to do that it got pushed back a whole bunch. Anyway here it is! Spitfire and her bab. Confused? Check out my blog! Want to look at this all the time? Here's wallpapers! Details of the printing forthcoming, because I'm going to be putting surplus stock of old postcards up and maybe doing more printing if there's demand! We shall see. There is stuff to work out.