As has been noted, beagles (and foxhounds) hunt by scent,and indeed in the picture that beagle is working his nose- so yeah, they have no idea what it 'looks' like. The look on a young hound's face, first time it sees what it's been smelling all that time, is in my experience a priceless bug-eyed, jaw- dropped expression. And more than once I've seen a fox and hound pop up nose to nose in heavy briars, fox says 'oops,' hound says 'huh?' and after a few nanoseconds the fox does indeed jump over the hound, sometimes, if that's the best escape route.
Hunting out west, not at all uncommon to look back behind first flight or second flight and see a coyote tagging along, watching the show.
As those of us with beagles know, it is all about the scent with them. When a beagle is on the trail it is oblivious to everything else. They are not really out to catch and kill the game, they just love following the scent. If you ever get a chance, go watch a brace beagle field trial. They are a hoot. Its take a step, bark, take a step, bark, come to a check, have a brief consultation to determine direction, the step, bark, etc. Dachshund field trials are also run in braces but dachsies are much faster and less accurate trackers than beagles. Dachshunds are killers at heart and deep down in their little short legged bodies truly believe if they run hard enough and long enough they will be able to catch and eat the rabbit.