Great photo. I think i remember this one circulating as to the absurdity of the pauldron in various costumes. Even Vader and Fett... Snowie with the teddy bear.. but the Sandie on the end... no pauldron. But he is also FX so that doesn't count. Classic. This photo had to be a decade ago. Good find!
"Find", nothing -- I've had that since it first went around.

I've been peripheral to the 501st since 1998. Not yet official. I have... Opinions™. And have more than once butted heads with command staff. For a group supposedly dedicated to film-quality-or-better costumes, there's a surprising amount of "LALALA I CAN'T HEAR YOU" when presented with whatever erroneous conclusions someone has already reached. Gawd, the hue and cry on the Pathfinders Detachment board when they made the flak vest mandatory, rather than optional --
it's in the frikkin' movie, guys!
I was meaning a chart like showing the uniform colors and types flowing from which organization etc. "All these are Stormtrooper corps". and "all these are Navy" "ISB" etc.. Quick reference chart.
I've been wanting to do that for a while, now, actually. Should I include Isard/Imperial Intelligence? Post-Disney-sale-Lucasfilm has been working hard to make me uninterested in the ancillary material I used to devour, so I have no idea if that old element of the EU has been worked back in in any way.
Also, i am still salty as well with various Legion discussions. We had a Garrison CO leave over it all. I cannot say i blame him either.
Star Wars fandom is the most opinionated bunch of moof milkers ever to exist. In my opinion.

And when their opinions are wrong, it's even worse.
Though pauldrons on Snowtroopers is technically "canonical" now, thanks to Battlefront II. But yeah, with the exception of other specialized Stormtroopers or officers, pauldrons shouldn't be worn by everyone.
There are a lot of things EA played fast and loose with for the sake of game mechanics. Some I can get behind, like colored markings on Stormtrooper armor indicating specialty training in certain equipment like flame weapons or explosives/demolitions. Other things are silly and immersion-breaking, like Luke fighting Boba Fett on Endor. Other things fall in between, like Snowtroopers with pauldrons.
I can accept some retroactive continuity. We don't see them on the Republic Troopers of the old days of three thousand years ago. They first showed up on the ARC Troopers in the Clone Wars microseries. That affectation seems to have carried over to at least some Clone Commanders. At least during the Clone Wars, it seems to be an indicator of advanced training and/or specialization.
Unless and until something definitively overwrites it, I try to incorporate as much from the old EU as I can. So far, I have the Phase I Republic Trooper armor we see in AOTC, an updated design inspired by the Republic Trooper armor of prior galactic conflicts. It proves less than optimal for modern battlefields, and the Phase II helmet was rolled out. The prologue of the PS2 version of The Force Unleashed -- set a bit after the end of ROTS -- shows Phase III Stormtroopers on Kashyyyk. Armor and helmet are a transitional blend of Clone Trooper and OT Stormtrooper elements and design cues.
Later that evolved into Phase IV -- armor we'd call Sandtrooper and helmet we'd call Solo. After the military adage, "If there is an opening, dirt will get in it" proved making the blue markings into physical slits was a bad idea, the helmet got further tweaked into Phase IVb (the earlier version retroactively becoming Phase IVa). The armor later got updated, too, but the 'a' variant remained in use in some specialized kit that saw less-frequent use, such as the Battle Armor, Arid Environment, High-Temperature (Sandtrooper). Later still, the helmet shape was streamlined a bit and additional minor tweaks to the armor resulted in Phase IVc (the ROTJ suit).
There's a whole big missing chunk of information, and I don't know how much will ever get filled in. In the Aftermath trilogy, the ISB locked down Imperial Center right after the Emperor died. Even after the Battle of Jakku, the Empire still held the center of galactic government. Mas Amedda, acting as Palpatine's deputy, wrested enough control to formally surrender to the Alliance to Restore the Republic. And that is the last I've seen of
anything involving Coruscant. Again until it's proved "incorrect", I like to think of that as the new-canon version of the Imperial Remnant, and have the armor evolving one last time into the Legacy style, as either Phase IVd or Phase V (I'm torn).
But. While pauldrons remained in use through Phase III and Phase IVa, by the time Phase IVb was in use, they were replaced by armor markings and "Shadow" status.
That makes a certain amount of sense but why have them on the bridge though? It's not like doing that job would require them to be on the bridge as opposed to anywhere else on the ship. One as the main security coordinator who reports to the Captain or the XO I can understand, but not 5 of them.
Real-world? "Hey, we have some black Imperial jumpsuits in wardrobe -- stick some of the extras in them to break up the monotone look of the Star Destroyer bridge crew pits." There's a whole bunch of stuff in universe that doesn't always make sense. Some things seem super-advanced (like antigrav tech), while other things seem stupidly primitive (Boba Fett's rangefinder -- even in 1978 we already had picture-in-picture technology). Droids are an odd inclusion. Things seem strangely non-networked, relying on physical connections or couriering. Maybe they had something a bit like Dune's revolt against machines. Maybe AI tried to take over at some point. But I can come up with at least half a dozen plausible reasons why they'd be up there instead of somewhere else on the ship, based on the general universe-building going on in the original two films.