Compressing PowerPoint Files
When using high quality images within a PowerPoint file, the PowerPoint file can end up being too large to email or to store easily. A large file may also run slowly on some computers. Below is a quick guide to reducing the size of the file. Note: this is a destructive process so you may wish to keep an original copy of the file and / or the images.
Within PowerPoint, click on an image in the presentation and select "Compress Pictures" from the Picture Format toolbar.
Untick "Apply only to this picture" to update all images within the presentation.
Select the new resolution for the images - "Screen" would be the ideal option for most presentations, "Email" will reduce the file size further.