I already knew IS and DT require a credit for editorial use, and I have just confirmed that in FT also. I didn't check the others. Of course, an image in an advertisement in a magazine does not require that, just images in articles, and I suppose the latter is the case cited by holgs.
DT:
http://www.dreamstime.com/faq37-do-i-have-to-give-credit-for-the-imageDo I have to give credit for the image?
Should you use the image for editorial purposes, giving a credit line is compulsory.
IS:
http://www.istockphoto.com/license.phpFor greater certainty, the following are “Prohibited Uses” and you may not: (...) 13. use the Content for editorial purposes without including the following credit adjacent to the Content: “©iStockphoto.com/Artist’s Member Name]
FT:
http://www.fotolia.com/Info/Faq#b14Am I required to add copyright information when I use a photo from Fotolia?
(...) The only time we require copyright information to be added is when the image is being used in conjunction with editorial use such as a newspaper or magazine story.
update: I didn't see that restriction in StockXpert and BigStock. What a shame!Regards,
Adelaide
