Images are a great way to engage an audience. A quick look on Wikipedia for the phrase “A picture is worth a thousand words” will return the premise of the use of graphics, be they drawings or photographs.
Binging pictures into a PowerPoint, Keynote, or Prezi presentation is easy enough. Pictures we take today with our digital cameras often contain much more resolution, and are much larger in file size, that is necessary for projecting during a lecture. Even the cameras in todays tablets and phones are overkill for projected images.
Large images take up space on storage media, are slower for the program to load, and if the presentation is located in the cloud, requires significantly more bandwidth to transfer.
Scaling images is a “best practice” for matching a presentations content to presentation delivery method.
Beyond the face-to-face presentation software, digital delivery to distance learners also has similar constraints with the bandwidth to transfer to the end user increasing in importance in the consideration of image quality and file size.