Facebook uploads getting insane engagement, external links ignored

I'm still pretty new at this and have been "split testing" which at my stage involves throwing a bunch of stuff at the wall blindfolded and seeing what sticks. I do prefer learning the easy way if possible though and have taken another posters advice to start playing around with different wordpress linking strategies. But using direct posting of youtube vids to my timeline I'm getting anywhere from unbelievably horrible to modest engagement but in a lot of cases I'm getting mind blowing, kiloton explosion engagement from simply uploading pictures. Is there a best way, or any way, to monetize the engagement coming from picture uploads directly to facebook? I was thinking about putting links on the pictures like some of these RayBan guys do, but no idea what the risk/reward picture looks like for that.

And when I say the engagement levels are different I mean some of my timeline youtube posts are getting literally no likes while picture uploads to the same accounts are getting close to 1000. Hard to believe facebook would be that blatant in its anti competitiveness. Any help or suggestions are much appreciated, thanks.