I inventeded it!
Sorta.
I came up with translucent captioning accidentally 4 or 5 years ago (with another account I was using at the time. I was playing with color selection code, and by accident tapped it when it was just 5 instead of 6 digits required, and BINGO!).
I showed a site Mod, and he took it to HQ and they developed into what you see now. Then sometime later came the same with images. Although he won't admit it to me, it seems rather evident than the same algorithms whatever that allows for opaque captions also allowed for opaque imaging as well. I believe he won't admit it because I've made jest of how I kind of got Edisoned out of it. I was credited with opaque lettering, but it was put as a group effort between three of us, as opposed to it was a mistake I made while selecting colors that turned out to be useful. So yeah, it took three to make it a thing here, but it wouldn't have happened if it wasn't for what I first did.
Did I get anything in return you ask?
A few months later, maybe the following year, the owner almost booted me out. I've never gotten a timer at the time, but it turned out the big ball swinging gun toting Fight Club watching First & Second Amendment quoting gents found me to be something of a meanypants and flagged everything I said. Although admittedly, back then what I said it was a tad bit thornier and rectal damaging than the lukewarm styrofoam puree you see me post now.