There are many ways to approach somsthing like this, Here is a variation on Rich 54 process
1. Duplicate the base layer (CTRL+J) Click on the eye on the bottom layer and make it invisible.
2. Image/Canvas Size (anything larger will do …say 6x8).
3. Magic Wand w/ contiguous and 3x3 average and tolerance 10.
4. Magnify to 200% or 300%.
5. Select the outermost black line with the Magic Wand and then copy to another layer (CTRL+J) You now have 3 layers.
6. That 3rd layer will be selected. Click the magic wand anywhere outside the black Hog outline.
7. At this point the entire area outside the Hog is selected by crawling ants (That’s why you made the canvas larger so that area would be contiguous.) GO BACK and click on the second layer so that the crawling ants are actually selecting/defining the colored area not blank space.
8. CUT (not copy) this colored area (CTRL+Shift+J) Immediately after that hit the delete key or make this cut-out layer transparent.. You have cut out and deleted everything around the Hog head.
9. DONE You will see that the Hog Head is floating in checkerboard transparency. There is some garbage under the head on that second layer that will need to be erased