Generally, unless you find an image whose description specifically says that it is released into public domain (or similar status), any and all images are automatically copyrighted upon their creation and therefore subject to copyright law. So assume that an image is under copyright (even its source is unclear) unless it is in the public domain. Alternatively, you can ask its creator for permission to use it.
You can find sources of public domain imagery on Wikipedia: http://en.wikipedia.org/wiki/Wikipedia:Public_domain_image_resources
Generally, anything that is not more than 80 years old can be assumed to be copyrighted unless you can prove it was not properly published with copyright notice prior to 1976. Anything created after 1976 is copyrighted until 70 years after the death of the author, or whatever Congress (and treaties) makes it in the mean time.
The more interesting question is "What is it worth?"
There is a new web-app. out called PicScout. (www.PicScout.com) that actually catalogs copyright information for online photos and allows you, once you sign up, to search copyright information for photos on the internet and purchase the rights to the photo. Similar to the pay-per-song model of many music marketplaces.
Any image appearing online would be protected by copyright unless specified otherwise. For example, some Flickr users choose Creative Commons licenses, and others (often public libraries) specify the images to be in the public domain, but this is clearly noted on the page. Everything else is protected.
Owning an image or the copyright to an image are the same thing. When you hold the copyright to an image it is yours to do with whatever you will, and you can decide who has permission to use it or not. There is no difference.
Copyright is automatic, so it will be the date the image was created.
If you wish to reuse a copyright-protected image, you need permission from the copyright holder or an exemption in the law.
It is safest to assume that any image created since 1923 is protected by copyright unless explicitly stated otherwise.
The image is still owned by and under copyright by the original creator of the photographer who created the ORIGINAL image. Taking a photo of someone else's photo does not transfer the copyright to you (the iPhone owner).
With permission from the copyright holder, yes.
Copywriting an image has to be done with the copyright office of your country. If you have uploaded the image to Facebook or other social media sites, you may not be able to copyright it.
No, because there's nothing to steal. Using an image without permission or an exemption in the law is copyright infringement.
The images in Monopoly are copyright, which means you will need legal permission from the games copyright holders to publish the image.
Yes There Is!
Yes, unless you own the copyright to the image, or have authorization from the copyright holder.
For the most part, you can assume that a given text or image is protected by copyright unless explicitly stated otherwise. Protection is automatic, and the term of protection is quite long. The real challenge is in finding out who the copyright belongs to.