High-resolution images in PPT slides can greatly increase the size of a PowerPoint file when they are embedded within a slide. Here is a quick way to compress the images and reduce the file size substantially, without causing a noticeable loss in image quality.

Steps to compress images:  Windows/Mac - Microsoft PowerPoint 2019?
  1. Go up to the Picture Tools Format tab.
  2. Click on the Compress Pictures command.
  3. Select your Compression options (see image below)
  4. Select your Resolution (see image below)
  5. Click OK.

Steps to compress images:  Windows - Microsoft PowerPoint 2010, 2013, and 2016

  1. Open your PowerPoint file.
  2. Select a slide that contains an image or picture.
  3. Select the image or picture.
  4. Click the Picture Tools ribbon at the top of the screen.
  5. Click the Format sub ribbon.
  6. Click Compress Pictures.
  7. Select the checkbox to Delete cropped areas of pictures option to reduce the overall size of the image or picture in the presentation.
  8. Chose Email (96 ppi): minimize document size for sharing.
  9. Uncheck Apply only to this picture if you want all of the pictures in the entire presentation to be compressed for smaller file.
  10. Click OK.

In most cases, 96 ppi is the best selection. Unless you plan to print out quality photos of your slides, this option will reduce the file size and there will be little difference in the screen output of a slide at 220, 150, or 96 ppi.

Steps to compress images: Mac - Microsoft PowerPoint 2016

  1. Open your PowerPoint file.
  2. Select a slide that contains an image or picture.
  3. Select the image or picture.
  4. Click the Format Picture ribbon at the top of the screen.
  5. Click Compress (to the right of the Transparency icon).
  6. Click the Picture Quality drop-down and choose Best for Sending in Email (96 ppi).
  7. Select the checkbox to Delete Cropped Areas of Pictures to reduce the overall size of the image or picture in the presentation.
  8. Apply to all pictures in this file is default and recommended for a smaller file. If you only want to delete the currently selected picture, uncheck that.
  9. Click OK.

Compression should take just a few seconds, but for files with many images, it could take up to a minute or two to process. Once complete, save the modified file and upload it.