The Internet contains a wealth of scientific and clinical images which can be used for study, teaching and research. Images may be included in electronic journals, individual documents on the web, as part of multimedia tutorials, presentations, lectures and so on.
JISC Digital Media provides advice and guidance for the Higher Education community on image creation, delivery and use and on digitisation projects and much of this is equally applicable to NHS staff. See in particular their review of image search engines
There is plenty of other useful material elsewhere on the site.
Always check on the site for information about copyright restrictions. Not all images will be freely available. You may need to seek the publishers' permission before copying any image.
To download an image to your PC, right click on the image and select Save Picture As. To insert into Word or PowerPoint, select Insert, then Picture. Locate the image file on your disc and insert.
Here is a selection of other image resources you may find useful.
Credit Spooky Pooka, Wellcome Images. DNA double helix illustration. Illustration of the DNA double helix structure first discovered by Watson and Crick in 1953. Digital artwork/Computer graphic 2005. Collection: Wellcome Images
This illustration depicts a dorsal view of the “Common fruit" fly, or “Vinegar” fly, Drosophila melanogaster, a member of the family Drosophilidae. CDC copyright free image from the Public Health Image Library.