Wesley Fitzwilliam Heinz Pinkerton VIII
Original art is pen and ink on 10 x 7 inch paper, but the illustration didn't fill all the space. Artwork is on a transparent background here, after preparation for Redbubble products. This cutie is available on different-colored backgrounds (white, pink, blue, and sand/tan), and a wide variety of products, including stickers and magnets and kids' clothing.
Edited to add: I changed the title of this piece over at Redbubble after a false copyright infringement claim. The accuser had done a keyword search, and words in the title and keywords were flagged, although there was in fact no copyright infringement. I am nearly certain this is a Jack Russell Terrier, so I changed the title to that. The links above still work.