This morning I was looking around the web in search of public domain images. I started with Wikipedia and soon found myself touring luscious museum sites.

Le Louvre
Rijksmuseum
Web Museum, Paris

Wikipedia says "Note: Accurate photographs of visual artworks lack expressive content and are automatically in the public domain once the painting's copyright has expired (which it has in the US if it was published before 1923). All other copyright notices can safely be ignored."

Hmm. So's who defines accurate? Most of the pictures of paintings I perused this morning looked photo-realistic, but their sites claim copyright to the photographs, not the works themselves. Web Museum has a great tongue-in-cheek notice:

USA lawyers section (NOT part of the legal agreement)

This product is meant for educational purposes only. Any resemblance to real persons, living or dead is purely coincidental. Void where prohibited. Some assembly required. List each check separately by bank number. Batteries not included. Contents may settle during shipment. Use only as directed. No other warranty expressed or implied. Do not use while operating a motor vehicle or heavy equipment. Postage will be paid by addressee. Subject to CAB approval. This is not an offer to sell securities. Apply only to affected area. May be too intense for some viewers. Do not stamp. Use other side for additional listings. For recreational use only. Do not disturb. All models over 18 years of age. If condition persists, consult your physician. No user-serviceable parts inside. Freshest if eaten before date on carton. Subject to change without notice. Times approximate. Simulated picture. No postage necessary if mailed in the United States. Please remain seated until the ride has come to a complete stop. Breaking seal constitutes acceptance of agreement. For off-road use only. As seen on TV. One size fits all. Many suitcases look alike. Contains a substantial amount of non-tobacco ingredients. Colors may, in time, fade. We have sent the forms which seem right for you. Slippery when wet. For office use only. Not affiliated with the American Red Cross. Warranty void if serviced by non-authorized personnel. Drop in any mailbox. Edited for television. Keep cool; process promptly. Post office will not deliver without postage. This can contains a head-enhancing device; do not shake vigorously. List was current at time of printing. Return to sender, no forwarding order on file, unable to forward. Not responsible for direct, indirect, incidental or consequential damages resulting from any defect, error or failure to perform. At participating locations only. Not the Beatles. Don't try this in your living room; these are trained professionals. Penalty for private use. See label for sequence. Substantial penalty for early withdrawal. Do not write below this line. Falling rock. Lost ticket pays maximum rate. Nap was here. Your canceled check is your receipt. Add toner. Ceci n'est pas une pipe. Place stamp here. Avoid contact with skin. Sanitized for your protection. Be sure each item is properly endorsed. Sign here without admitting guilt. Out to lunch. Slightly higher west of the Mississippi. Employees and their families are not eligible. Beware of dog. Contestants have been briefed on some questions before the show. Limited time offer, call now to ensure prompt delivery. You must be present to win. No passes accepted for this engagement. No purchase necessary. May be hazardous to health if consumed in excessive quantities. Not responsible for typographical errors. No returns unless defective. Processed at location stamped in code at top of carton. Don't even think about parking here. Shading within a garment may occur. Use only in a well-ventilated area. Keep away from fire or flames. Replace with same type. Do not put the base of this ladder on frozen manure. Approved for veterans. Booths for two or more. Check here if tax deductible. Some equipment shown is optional. Price does not include taxes. No Canadian coins. Not recommended for children. Under penalty of law, this tag not to be removed except by consumer. Prerecorded for this time zone. Reproduction strictly prohibited. No solicitors. No alcohol, dogs or horses. No anchovies unless otherwise specified. Restaurant package, not for resale. List at least two alternate dates. First pull up, then pull down. Call toll free number before digging. Driver does not carry cash. Some of the trademarks mentioned in this product appear for identification purposes only. Objects in mirror may be closer than they appear. Record additional transactions on back of previous stub. Unix is a registered trademark of AT&T. Do not fold, spindle or mutilate. No transfers issued until the bus comes to a complete stop. Package sold by weight, not volume. Your mileage may vary. This supersedes all previous notices.

It is confusing as hell to know what you can use and what you can't. Furthermore, the terms of the GPL can tie one's hands. If I find a perfect painting to illustrate a point in my book, I may not be able to use it because I would be required to share the content of my book in its entirety under the same (free) terms. I don't think my publisher can dig it.

It is okay to reproduce these here, at least so long as I don't back up my site (i.e. make additional copies.)