This should be printed at 300 pixels per inch resolution. I have a much larger version for people with really good printers. Mine unfortunately only does 300, 600, and 1200 pixels per inch and nothing in between or above, so I screwed myself over because after putting all the work into the card which was optimized for 1500 pixels per inch, I couldn't print it properly without resizing it. Furthermore my printer won't line up the front and back even though I tell it to print in the center of the page, so I wasted ink and two sheets of cardstock. Arrgh.
At any rate, you print this on cardstock at 300 pixels per inch so it's about the size of a credit card. Then you print your Jolly Roger on the opposite side (or if your printer is stupid and won't line it up, print it separately and use rubber cement, not other glues because those cause wrinkles), and put it in your wallet. ARRRGH!