In the ad, the man they showcase her with looks unimpressed by her figure.
Naomi Campbell and Skepta then feature in the "after" shots.
Despite the fact that the "before" and "after" pictures clearly feature completely different people, the advert claims to be showing the results of a diet patch.
Eagle-eyed shoppers soon spotted Barber on the commercial, with one person tweeting:
"Did you know some company on @WishShopping is using your photos to sell diet patches??
"I love how funny your photos are but I figured you should know!"
After being alerted to Wish Shopping's advert, Barber tweeted the company, slamming them for stealing her images and using them to sell body-shaming products.
"Hey @WishShopping what's this all about? You can't use my photos especially to sell body shaming products."
Barber's fans have since leapt to her defence, saying "that's appalling!" and "they've taken your brilliant irony and they're using it to make money".
The slimming patches page on Wish has since been taken down.
Barber has more than 5 million Instagram followers after making a name for her parody fashion shoots.
