I finally found the origin of many of these images and some of the phrases so commonly found on them...The 4chan.org image board
. (specifically, "Animals & Nature")
The origin of the word "harbl" (took me awhile on this one, but found on Urban Dictionary
This word has its origin on the 4chan imageboards, more specificially the "/b/ - Random" imageboard there. The moderators on that board sometimes install wordfilters that change certain words or phrases to other words and phrases when a post is made and much hilarity ensues. A recent example for this was when "FTW" (For The Win) was wordfiltered to "SUCKS". Similarily, at some point the word "c**k" was wordfiltered to "harbl" because the moderators got tired of the meme "I'll suck your c**k" which of course then always read "I'll suck your harbl". Since this was almost 2 years ago many newer users don't know the origin story (so to speak) and just use it as a random (pun intended) nonsense word. Most recently it has become integrated in the "I'm in ur ______ verb+ing my/your ______" meme.
A meme of which the origins can be found here:http://www.donationc...53.msg42270#msg42270
(thanks again, housetier)