"Oops! Kylie Jenner posted a photo with an error in Photoshop, but it was on the air for only 20 minutes after it was deleted," another said.
Others described the "bent" pool edge as a giveaway of the editing, asking how she was "still having Photoshop fails".
Some said it was "sad" she felt the need to alter her images, adding it was setting "unrealistic standards" for others.
A compilation of snaps from the same shoot remain on Kylie's Instagram, alongside the caption: "Taco Tuesday."
The pool edge in these snaps looks as it should, with no visible curve.
On Monday, Kylie put on another provocative display as she isolated in the sunshine.
The 22-year-old cosmetics billionaire posed poolside in a skimpy black bikini.
The youngest Kar-Jenner showcased her hourglass figure as she lounged outside her new lavish $60 million mansion.
READ MORE: • Kylie Jenner drops $60 million on lavish LA mansion
She was pushing her Kylie Skin range as she applied sunscreen and reminded people to use sun protection.
"Don't forget your SPF," she captioned the Instagram picture.
It's not clear whether the mother-of-one has moved into her new home or was just using it to film.