Full HD 4k Presentations

In most cases, a normal-sized image (3” x 5” original) at 150dpi should work fine. Once you insert it into a PowerPoint slide, you may find yourself with a need to enlarge it. At 150dpi, you will be able to roughly double its original size and have it still look fine on the screen.
As a recap, in PowerPoint, go to File, Options, Advanced. And check the option Do not compress images in the file at the Image Size and Quality group. With this option set, your high resolution images, will remain high resolution, when they are stored within your presentation.