'The Bachelor' Dragged for Worst Bikini Photoshop Job Ever

"The Bachelor" is guilty of a huge fashion faux pas -- or a digital one, anyway -- sloppily covering up bikini bottoms with what looks like Sharpies. Really. It's comical.

If ya missed it ... Monday's episode took Bachelor Peter Weber and his dates to Costa Rica for, among other things, a bikini photo shoot. Problem was ... the girls were apparently dressed too risque for someone -- either 'Bachelor' or ABC honchos. So, as they say, they fixed it in post-production ... by, literally, drawing more material onto their bikinis to cover the butt cheeks!!!

You really gotta see how bad it is to believe it.

When Peter and Sydney took off to a hot tub for a one-on-one date, the cover-up job makes it look like her bikini is 2 sizes too big.

During Lexi's time at a waterfall with Peter, her blue bottom looked ... just off.

The botched editing didn't go unnoticed ... with one hawk-eyed fan calling Victoria F's red bottom a terrible MS Paint job. Then there was Victoria P ... whose yellow bikini was made to look like she had a flap on her backside.

At least with Kelley's, bikini-print bottom editors decided to use the same print and color for the alteration ... but, again, it made it look like she was straight-up wearing an adult diaper. Depends on your perspective.

As for who screwed the pooch -- we've reached out to 'Bachelor' reps. No word back, but seems like a lock no one in post is getting a rose this week.