Reducing Image File Size Squeezing Graphics Files for use in PowerPoint This is a brief introduction to some of the concepts and technical details of reducing the size of image files so that they can be imported into PowerPoint without creating a 40Megbyte monstrosity. Graphics files captured using NIH-Image, or scanned using Photoshop can easily grow to upward of 10Megbytes in size. If you have a PowerPoint presentation with 10 such images your PowerPoint file will be over 100Megs. The solution to this problem is to squeeze each image down in size so that the images in your presentation are each as small as possible. Note that once the images are in PowerPoint it's too late to shrink them.
Some forethought is required.
First a quick reminder about file sizes on computers. Now back to the original question. If your images are bigger than that then they contain more information than they need to for screen viewing. My recommendation is that if your image file is larger than 200kB, think about reducing it's size. A presentation with 20, 200kB images won't be much larger than 4MB which is a perfectly reasonable size for a PowerPoint file.