A designer is drawing attention to art he designed for Spike Lee's new film Oldboy, which he says was used without his permission after walking away from the ad agency that commissioned them.

Juan Luis Garcia posted an open letter to the director on Wednesday, saying he was contacted by an ad agency earlier in the year to create concept designs for posters that might eventually be used for Lee's new film, which opens this weekend.

Garcia says he was told that Lee chose to use his designs, but the agency made "an insultingly low offer" for the work, saying the exposure would be worth it. He declined, and that's when Garcia said things got ugly.

Oldboy comp - Juan Luis Garcia

Designer Juan Luis Garcia posted his original concept art for Spike Lee's Oldboy, left, alongside the official poster used in promotional spots. Garcia's concept was later posted to Lee's Facebook page. (Juan Luis Garcia)

"They told me that I didn’t want to mess with Spike Lee, that I would never work again, that I was a despicable human, that they wish they never met me," he wrote.

Garcia's mock-ups were then posted to Spike Lee's promotional Facebook page, with Lee's copyright added to the images. Garcia's name does not appear on the images.

One of the movie's official promotional posters also strongly resembles one of Garcia's mock-ups. He posted a side-by-side comparison of the two on his blog.

Facebook users flood Lee's page

In an email exchange with The Hollywood Reporter, Garcia says he has been overwhelmed by the response to his open letter. "My inbox is being inundated with support from the design community," he says. "This seems to happen far too often and simply isn't right."

He also explained why he chose the public route, posting an open letter instead of taking legal action. "I don't want to sue anyone, it's not in my nature," he said. "I'm thrilled [Lee] liked the posters and hope they continue using them, but I need to be remunerated."

Users have bombarded Lee's Facebook page with hundreds of comments that include links to Garcia's open letter, calling for the designer to be paid for his work, or to remove the images.

"The person who designed this poster has not been given credit or compensation," writes Facebook user Graham Post. "The fact that it's not being used in the director's public Facebook account is disgraceful."

Lee responded to the controversy on Twitter Wednesday, saying he has never heard of Garcia, calling the open letter a "cheap trick."