Script to scrape page for a cover image for recipe?

I'm making a recipe to capture an online periodical. The cover image is always on the front page with a file name like "cover0212_227033.jpg" where the "0212" portion is the month and year and the "_227033" is random. So if it had to use a regular expression, I think the script would need to look for (if that helps).
Is there a way to put this into the Calibre recipe to grab the cover?
Thanks,
Ari