What is seen: Banana slipping on a human.

What it is making fun of: Human slipping on a banana.

Definition of: irony

"Incongruity between the actual result of a sequence of events and the normal or expected result"

Example: If you have a phobia of longs words you have to tell people that you have hippopotomonstrosesquipedaliophobia.

It is ironic because the statement starts normally, and by the end one expects the phobia to have a short name. The irony arises from the fact that it doesn't.

Definition of: role reversal

"A situation in which someone adopts a role the reverse of that which they normally assume in relation to someone else"

What this image is not: The above image is not ironic because there is no normal, sane sequence leading up to the unexpected result. A banana walking up to an object, is already not normal. Furthermore, one already expects the banana to trip, since it follows the common act of tripping on a banana (done in reverse).

What this image is: Role reversal done for comedic purposes.

See: In Soviet Russia role reversal jokes (which are not ironic either).