Reader question:
How do I say "照片必須是原創且未經修改"in English? I'm not sure if I can say "photos must be original and unedited"?

My comments:
Yes, you can say that. In fact, you've done a good job.

"Original" means a photo is made by the person who's entering a photo contest ("Photos must be original and unedited" sounds like a regulation of an amateur photo contest). It means the contestant has taken the photo himself - instead of borrowing it from the professional photographer who lives next door or downright stealing it from a website over the Internet.

"Unedited" means the photo is in its original state without further human interference, or putting it nicely, artificial treatment. With Photoshop, ACDSee and other photo editing software, there are innumerous ways to re-do a photo printout.

Open a picture with ACDSee 6.0, for instance, you'll see you can modify a picture by re-sizing (cropping or cutting), adjusting image exposure (making it look brighter or darker), changing color-depth (giving it a reddish hue, for example), applying special effects (giving it an oil painting look and such like).

By editing, you alter a picture by giving it another, usually prettier look. To ensure authenticity and to create a level playing field, contest organizers therefore often demand that photos submitted must be original, previously unpublished (the public will be seeing it for the first time) and not digitally enhanced (no photo editing is applied to make the picture look smarter than it is). And most of the time, composite photos are not allowed.

A composite photo is a picture made by arranging parts from two or more pictures.

Here's a composite seen yesterday from a story (The Pentagon's not-so-little secret) at Salon.com:

Caption: Composite photo of George W. Bush and soldiers from the 1st Infantry at Fort Riley, Kan., who will be deployed to Iraq as part of the troop surge.

Zhang Xin is Trainer at chinadaily.com.cn. He has been with China Daily since 1988, when he graduated from Beijing Foreign Studies University. Write him at: zhangxin@chinadaily.com.cn, or raise a question for potential use in a future column.