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Posted by Michael Allsop on 01 July 2011
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Compressing pictures in Microsoft PowerPoint 2007
A common problem with presentations that have been created in Microsoft PowerPoint is the size of the file. PowerPoint never has been the most efficient user of memory space and if your presentation contains several high-resolution images or pictures taken straight from a digital camera, along with animations and other features, then the file may be many megabytes in size. This can cause your computer problems when it tries to open or save the file and it can be a nightmare to email it if your, or your correspondent's, network has an automatic block on large attachments.
There is, however, a feature that is easily overlooked in PowerPoint which enables us to compress a picture and save it at a size and resolution suited to the purpose of the presentation, whether for printing, projecting on a screen or just for viewing on a computer monitor.
In this blog we'll be using one of Microsoft's sample pictures (which starts at 762KB, so not too huge) but will see the benefits of properly managing this image.
First, a new presentation has been created and the image inserted onto the slide:
This has been achieved by clicking Insert -> Picture on the Ribbon
As it stands, this single-slide presentation is now 823KB in size. If the final presentation was to contain, say, 20 similarly sized pictures it could start to get rather unwieldy.
To overcome this, the picture can be compressed to a suitable resolution which will greatly reduce the file size. With the picture selected, the Picture Tools -> Format tab on the Ribbon gives us the following option:
NB: you will only see the Picture Tools -> Format tab on the Ribbon if you have a picture selected, otherwise it won't be there!
Clicking this option brings up the following dialog box:
Decide whether you want to compress all the pictures in your presentation, or just the one currently selected (in which case tick the box)
Before clicking on OK, make sure you first decide on what resolution would best suit your presentation by clicking Options... to see this dialog box:
Here, the 150 ppi (pixels per inch) setting has been selected - a good compromise between quality and size
The OK button should now be clicked on this dialog box, and similarly the Compress Pictures dialog box should be accepted.
Now, when the file is resaved, the file size is only 182KB, a saving of 641KB, or 78%!
The sharp-eyed among you may have noticed another option in the last dialog box - the option to Delete cropped areas of pictures. By default if you crop a large picture so that you are only viewing a tiny part of it on your slide, the full image is still stored in the file taking up lots of space! By deleting the cropped areas, PowerPoint will only save the part of the picture it needs, thereby further reducing your file size.