None of the following is intended as legal or other professional advice. It is a no-nonsense, logical approach to understanding and respecting copyright.
There are two main ways of infringing upon someone else’s copyright in the world of blogging and the internet:
1. Either you are making an actual copy of their image, uploading it to your own site and either passing it off as your own, giving no credit where credit is due, or (and most people don’t see this as infringing on copyright, but it really does) making the copy and giving credit, but the owner of the image does not actually want it to be available anywhere else on the web. Basically, they want their own site to maintain exclusive publishing rights to the material.
Most countries have a little lee-way when it comes to copyright protection and apply a 10% rule. If this was not the case, no person would be able to quote another person without gaining their explicit permission, which is just ridiculous. So, for the most part, I can quote 10% of someone else’s post, provided I attributed them as the source of the information, without getting into hot water.
Images are a bit different though. You can’t use 10% of an image… And don’t try to crop out 10%, or change it so that only 10% remains! Some owners of copyright for images do not allow for modifications (while some others do).
That having been said, most courts and jurisdictions normally require someone to prove actual “damage” in order to be compensated. If you used the image without consent, but did not actually make any money from it, that would still violate legal principles, but the copyright owner may not be able to get any real value of compensation from you, unless the copyright owner normally sells the content and you now give it away for free (for example, pirating movies via torrent sites would likely cost you a lot if the movie-makers instituted civil action against you).
When embedding a YouTube video into WordPress, WordPress does not actually add a copy of that video into your image gallery. The url still remains the same and whether someone views it from your blog, or the YouTube website, it is still viewed from the same (YouTube) URL and, in effect, you copied nothing. If the video is removed from YouTube, it will also be inaccessible from your blog.
Presumably, the individual who uploaded the video to YouTube had the right to do so. They need an account with YouTube and YouTube’s terms and conditions require that the person doing the uploading must give them non-exclusive publishing rights to the material. So the owner can still distribute it through other channels, but YouTube is allowed to be one of the distributors.
Because it is still viewed via YouTube even on your WordPress blog, it is still distributed by YouTube.
So, provided that you do not contravene the second no-no of copyright below, you should be okay!
2. The other (main) way of stepping on someone else’s toes, is to try to make money from something that they distribute for free. Simply because they are giving it away for free, does not give you the right to sell their (intellectual) property or to make money from its use. If you do so, the copyright owner is entitled to sue you for damages.
Some sites, like Flickr, have been formed where some of the contributors (not all, so make sure to filter for “commercial use allowed”!) are willing to give away their images for free, even if you use it to make money – provided you give them the necessary credit, without implying that they are endorsing you. Also, be sure to thank them politely, it is just good manners! Photographers and designers often allow the free use of some of their images to get exposure for their work, as opposed to paying for advertising on other sites, so people will be willing to purchase some of their other images.
Other sites sell you the right to use images and media, either for a once-off payment, or using some form of royalty system.
So, the main thing when using media without paying for it is that the donor for the image must be a consenting donor.
This consent can come from a notice, displaying a “Creative Commons” license (make sure to read the conditions).
But actually, the best way is just to ASK 🙂 In general, bloggers and artists are friendly people. They don’t like thieves, but they will usually let you borrow with permission!
The following is some really great advice by Christina for photographers, wishing to mitigate the possible financial damage of others using their work without their permission:
Basically, by reducing the resolution of the images, although they still display fine on the web, people cannot reproduce them in print with good quality. Prints are normally a more profitable market. So, your image will probably not be displayed on a bill-board without your knowledge!