How you are using the image guides your search for an image with a license that allows for your intended use. Most images are okay to use in live lectures and presentations as long as you are not publishing the materials for a public audience (e.g. on the web, in a book, or other publication). If you need an image to use for a publication, you’ll have to find an image with a license that allows you to do so, or get permission from the copyright holder.
Things to consider include:
No matter which option:
Images you find may have usage rights that have been spelled out by the owner. Here are some common terms to describe allowable use and their definitions:
Fair Use is not black and white. Rather, you use four factors to make a balanced assessment as to whether your use of an image (or other works) qualify as fair use:
Creative Commons is a set of public copyright licenses that enable free distribution of an otherwise copyrighted work and allow copyright owners to specify what rights they are granting. Copyright owners can clearly designate the extent of reuse rights and users get certainty about what they are allowed to do.
Attribution. The most open of the CC licenses, CC BY requires only attribution of the copyright owner. Users can reuse, revise, remix, redistribute, and retain the content.
Others can remix, tweak, and build upon your work even for commercial purposes, as long as they credit you and license their new creations under the identical terms.
Allows for redistribution, commercial and non-commercial, as long as it is passed along unchanged and in whole, with credit to the copyright owner.
Allows for remixing, tweaking, and building upon copyrighted work non-commercially.
Allows remixing, tweaking, and building upon copyrighted work non-commercially, as long as the owner is credited and license new creations are licensed under the identical terms.
Allows downloading and sharing of the copyrighted work as long as owner is credited. Neither derivatives nor commercial use of the work is allowed.