Creative Commons: Search engine for open source images, audio, and video.
flickrCC: This section of Flickr offers images that are available under a Creative Commons license and also explains the different types of Creative Commons licenses.
Google Images: While not all images on Google Images are Creative Commons licensed, it is possible to limit your search results to only images available under a Creative Commons license. To do so, run your search in the standard Google Image search bar and then on the results page, click on the "Tools" button just below the search box. Another drop down menu will appear with "Usage Rights" as an option.
Multicolr Search Lab: This tool from TinEye allows you to search for Creative Commons-licensed images by color.
MorgueFile: As macabre as this sounds, it's merely a free photo archive. No dead bodies here!
Color is a very poweful tool, but you have to be careful about how you use it, especially with text. Avoid using complementary colors (red/green, blue/orange, purple/yellow) as text and background colors. It is much easier on the eyes to use light text on a dark background, or vice versa.
Color is useful for emphasizing and focusing your viewer's attention. In the slides below, one's eye is immediately drawn to the colored text and the color photo first.
Comic sans is cute, but not appropriate for a professional presentation.
