(CNN) Canadian Green Party leader Elizabeth May, who built her platform on sustainability, said she was "shocked" to find her team had doctored a press photo of her to remove a disposable cup.

An archived version of the Green Party homepage back in June shows the original photo of May holding the compostable disposable cup. Then, an archived version of the same page in July shows the photo has changed -- instead, May is holding a plastic reusable cup with the Green Party logo and a metal straw.

In a statement on Tuesday, May said she was "completely shocked" to hear of the manipulated image, which she said was taken last year in Sidney, British Columbia.

"My personal daily practice is to avoid single use plastic items 100% of the time," she said in the statement. "I never drink from plastic water bottles. I always carry my own reusable coffee cup. I carry my own bamboo utensils. I walk the talk every day."

"I hope that despite this misstep by well-meaning party staff (who hoped to brand the image with our logo), people can believe that in the original photo there is nothing I would have hidden," she said.

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