Kim Kardashian says her daughter had to be edited into a family Halloween photo 'cause the kid was scared of Kanye's costume -- but only as a dinosaur ... not a giant mutant bug.

Kim posted a couple of decked-out Halloween pics over the past couple days, and it looks like the Kardashian-West fam went with "The Flinstones" and worm themes this year. Funny enough, Kim admits little Chicago had to be photoshopped into the former shoot, seeing how she was apparently terrified of dad in the life-size Dino outfit and wouldn't get near it.

On the flip side ... it looks like Chicago was able to pull it together for a way creepier family photo, where everyone dressed up as bugs -- or as Kim puts it, "West Worms."

If you ask us, Ye looks a lot scarier and more menacing as the fly/gnat/larva ... whatever the hell that is ... as opposed to the lovable Flinstones pet. But, hey, to a 1-year-old ... maybe Dino is the freakier sight. Better not put any Barney on around her ... just a suggestion.

Of the photoshop job, Kim said ... "This family pic was such a challenge because Chicago was so scared of Dino! LOL We tried to explain and show her that it was just daddy but she didn’t get the concept yet!" She went on to add, "So shout out to the photographer for editing her in & making our family Flintstones dreams come true!"

Kim also posted a BTS video of her and fam wearing their bug outfits -- set to soprano Lorna Anderson's soothing voice -- and it looks like Kanye had to win Chicago over there too.

Kids, man ... gotta love 'em.