One Internet user said that he found the image strikingly similar. "The same picture was hanging on the wall of my mother's home," said the man, surnamed Li, from southwestern Sichuan Province. "The two images are almost the same except the one on my mother's wall is lighter in color."

The comments and pictures Li posted all but convinced observers that Zhou's tiger photo was a fake. The publicity surrounding the on-line controversy brought the case to Vista's attention, the company has said.

Zhou, for his part, has repeatedly said that the Zhejiang company had infringed on his copyright. "The company is on verge of bankruptcy and is trying to bully me," he said in an interview with the Nanjing Morning Post.

Meanwhile, Guan Ke, a publicity official with the provincial forestry department, has described the Zhejiang company's poster image as "a fake photo fabricated in a ridiculous way using Photoshop." Guan has come in for some criticism, with his comments described in media reports as an attempt to gain publicity and tourism revenue for the province.

The People's Court in Yiwu City on Monday accepted the lawsuit filed by Vista Printing and Wrapping, which is demanding 10,000 yuan (US$1,370) in compensation from Zhou and 20,000 yuan from Guan, for damage to its reputation. The firm also wants a public apology.

Guan wrote in his blog that he was "delighted" to become a defendant in the case. "I should indeed thank the brave prosecutor for seeking the opportunity to unravel the truth," he said.

In early December, State Forestry Administration demanded that the provincial forestry department have the photo authenticated by a panel of experts, but no results have yet been published.