Images that will appear as freestanding images in the catalog should be isolated with a clipping path, rather than flattened or pasted against a white background.

http://www.google.com/search?q="isolated with a clipping pat...

Also, see here:
http://www.proz.com/kudoz/german_to_english/photography_imag...





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Note added at 4 days (2009-05-12 08:29:12 GMT)
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Here are a few more useful references for this term. The following page describes and demonstrates the concept of isolating an image:

http://www.sitepoint.com/article/masking-techniques-photosho...
"Isolate objects. Extract objects. Cut out an image. Remove a background. Call it what you will, each of these phrases describes the same objective: take a photo and isolate an object in it from the rest of the image, without the background."


http://www.all-things-photography.com/how-to-isolate-objects...

http://www.createblog.com/photoshop-tutorials/14007-how-to-i...