PowerPoint Bug Alert!

Automatic Image Compression Is Messing Up Your Files

Steve Sheets, Technical Director

Steve Sheets

Jun 14, 2018

PPT has image compression settings that are specific to every file and they're likely messing up your decks every time you save. So far, it seems like Mac users are not affected but for PC users it has been a major thorn in our side recently. 

If the compression settings are set to a high quality, it can bloat the file size (a lot!). If it is set to low quality, it makes the images pixelated. Even if the settings are somewhere in the middle, there is no sweet spot, it still makes the file bigger than need be and degrades images. What makes this so bad is that this is a file setting that runs automatically every time you save! Fortunately, your friends at GhostRanch are here to show you how you turn it off:

Click File > Options.

In the Options box, click Advanced.

Under Image Size and Quality, select the Do not compress images in file check box.

Unless turned off, these compressions are running every time a file is saved on a PC. So, please be extra careful and start the habit of always checking the settings on your PPT files. While in most cases the results of this may go relatively unnoticed, we have also seen some files more than triple in size. Meanwhile, things like logos and icons are getting maimed left and right by even mild compression as these types of images are particularly susceptible to pixelation.

We may not have a catchy tagline like "be kind, rewind" but please, be nice to your server space and your images, and "turn off compression, it's a healthy obsession".

For anyone curious as to "How would image compression make a file size go up?" —” well, get brownie points for the excellent question. PPT turns images into PNGs when it compresses them. This is good in that once it is compressed, unless settings are made to an even lower quality, the image will never change again. Were you to keep saving a JPEG as a new compressed JPEG it would get a little uglier every time due to "jpeg artifacts". The only problem is, JPGs are very good at making image files small, so, as soon as you run image compression in PPT, it is likely that you are turning multiple JPEG files into much larger PNG files. Multiply this problem across a handful of images and all the sudden that beautiful PPT you could email is now 100MB, or if you did manage to get the file size low, your logos and icons may look like they are made out of legos instead of pixels.

So what should you do if you need to compress your PowerPoint file? Options are kind of limited but there are three scenarios which can produce a small file size without creating an ugly deck. The most time-consuming way is to compress images before they are put into the deck. This is not a bad way to go if you have a compressed library of images to pull from but can become cumbersome in most circumstances. Another great option is to run NXPowerlite and use that for compression. It works great and the folks over there (Hi Andy!) have been very good to us. The third option we sure hope it's the easiest, just to reach out to the friendly people here at GRC, we'll get you squared away and looking good!

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About The Author

Steve Sheets, Technical Director

Steve is a designer with high expectations for a final product but he tends to obsess over process too. He likes to know the many ways to get things done, the advantages of each and their oh so scary pitfalls. Perhaps that's why he has a Mac and a PC?

"Workflows are one of the few times in life where the best way tends to be the easy way, the trick is figuring out what's 'easy' for your specific situation."

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