Today it is very easy to scan images on a computer and copy pictures and illustrations from the Internet, including tables and graphs. In fact, it is available any time you "right-click" a computer mouse. But that does not mean that it is okay to make the copy. The same copyright compliance given to written property must be observed for images. Be sure to put the copyright symbol, name, and date on each copy, and cite your source. Use "thumbnail-size" images as a reference or a mnemonic tool.
See this tutorial to check whether the digital image you want to use can be used: http://www.netknowhow.ca/nkhcrimg.html
You may make a copy of an image once it passes into the public domain. See table, When Does a Work Pass into the Public Domain? to determine if the work is in the public domain
Use in a class setting is okay, provided fair use guidelines are met. If it is to be used outside class, check at the source to determine copyright permission.
Use of many copyright images requires obtaining permission from the copyright holder. See Microsoft's description of what can and cannot be used: http://www.microsoft.com/about/legal/permissions/default.mspx
Illustrations and photos from many government sites may be copyright free, but the use of these "copyright-free" images may still have certain restrictions. For instance, the use of agencies' official emblems to implicitly or explicitly endorse any product, organization, policy, or agenda is strictly prohibited by law. Be sure to read the copyright statement at the particular site of the document you are using.
Clip art is sold to be copied. However, it is important to pay attention to the restrictions set by clip art publishers. Look for the copyright statement whether as part of a software package, a print volume, or a web site. The rights given may be limited, such as "limited personal use of up to twenty images only".
For instance, Microsoft ClipArt Gallery is a searchable gallery of copyright free images if you have their Office software legally installed on your computer. Its copyright statement in the end user license agreement (EULA) includes the following among its restrictions:
If you believe you are overstepping the uses set forth in the copyright license, it is prudent to write the copyright holder and ask for permission.
Cartoons are treated like any other image for copyright. For use
outside the classroom, permission must be obtained from the copyright
holder. Cartoon copyright owners generally have very visible copyright
policies on their web sites.
The New Yorker has a web site devoted to licensing its cartoons: http://www.cartoonbank.com.
United Media, home of Dilbert and Peanuts, allows you to download
desktop wallpaper but when it comes to presentations, they request that
you seek permission. There are often special rates for high school and
college students and non-profit organizations. See their copyright file.
To
use a strip for a presentation, newsletter, book, memo, or any other
type of distribution, you need permission from United Media. Permission
is granted on a case-by-case basis. Please send a letter or fax with a
copy of the strip or article that you wish to use and a brief
explanation of how you intend to use it. If you wish to submit your
request by email, please use the reprint permission form.
If you
have the release date for the art or article, it helps us process your
request faster. Please include the type of publication (or topic of
presentation) and the circulation of the publication. There are also
special rates for high school and college students and non-profit
organizations. See library staff for assistance, as you would for any
other type of image.
You are responsible for copyright permission for your own web site.
Just because something is on the Internet and is easy to use, does not mean it is free to use! Be sure to cite or attribute what you do use appropriately. Internet resources often combine both copyrighted and public domain content. Use care in downloading any content from websites. Check site to see if permission should be requested or if allowed.
Be aware of the copyright ramifications of including embedded additional links to that particular site. Deep linking to pages several levels deep within a site may also lose this context and raise the objections of a site owner. These are at the very least courtesy situations and may be considered contributory infringement. In losing context, you may obscure attribution.