How do you print a picture from Facebook on the iPad Air2

tap on the photo to make it big. Then hold your fingers down on it to see if the dialogue comes up to save it. If it does, go into your photos app, find the photo you just saved and print it using airprint (presuming that HP printer is air print enabled, if not you may need to look for a third party app to do your printing

After enlarging the photo you might have to take a screen shot then print that from photos. When you hold you finger on the photo then tap save photo it's doesn't seem to be saving to photos.