It seems that the attitudes of web sites vary quite a lot.

Here, for example, is what the Epson Photo Center says about pictures that people post on the Epson site -

"Copyright

All right title and interest in individual photographs posted on the Site will remain the exclusive property of the individual owner of the applicable photograph, and Epson claims no copyright or other proprietary right in these works. However, Epson does hold a copyright in certain portions of the Site and in the entire contents of the Site (in the aggregate) as a collective work under the United States and other copyright laws. You may display and, subject to any expressly stated restrictions or limitations relating to specific material, download portions of the material from the different areas of the Site solely for your own non-commercial use. Any redistribution, retransmission, or publication of any material or content on the Site is strictly prohibited without the express written consent of the copyright owner. You further agree not to modify or delete any proprietary notices from materials downloaded from the Site."

The difference is remarkable.to say the least.