3. Normalising picture resolutions.
A common cause of large file size is picture resolution that is higher than it needs to be.
XP/03: right-click on any picture, then click [Format Picture]. Click the [Picture] tab, then [Compress].
Select [All Pictures in document] and [Web/Screen]. Check both [Compress Pictures] and [Delete Cropped Areas].
It's advisable to save the presentation as a new version to see how much difference it has made, this can be huge or very little, depending on what sort the pictures are and where they came from.
PowerPoint 2007 developed this by doing a basic compression automatically when saving - a rare case of Microsoft taking a good idea and improving it! It’s still a good idea, though, to do this -
07/10: Select any picture, then click the [Format] tab. In the [Adjust] box, click [Compress Pictures] then [OK]. Again, to be safe, save as a new version and compare the picture quality. Don’t just click ‘Save’ because then there’s no going back!
To give you an idea of the difference this can make..... we recently had a 30Mb presentation which, with 30 seconds work, came down to 950Kb - if nothing else, it’s a little easier to email.