As a helpful full-stack developer, I'm always willing to lend a hand with general problems related to IT and digital marketing materials.
One such problem cropped up this week - PowerPoint presentation bloat.
We had a fairly simple 40 slide PowerPoint presentation that had somehow grown to 200Mb in size. There was a bit of a panic, because this presentation needed to be made available for 2,000 users to download - so I was asked if I could take a look.
PowerPoint has built in optimisation tools - which will downsample or crop images to save space.
However, I often find that they are either too aggressive (leading to pixelated images) - or perhaps not aggressive enough - making little to no difference to the size of the document.
One tip I've found over the years, is to remember that PowerPoint documents are actually just ZIP files.
If you rename a PPTX file to .ZIP, you can open it in Windows Explorer (please make sure you do this to a copy of the presentation file, not the master file!)
Once you have the ZIP open, look inside ppt/media, and you'll find the raw media assets that form the presentation.
If you sort the folder by size, you'll soon find out what's responsible for the bloated file size.
Some examples I've seen that contribute to file size bloat:
With something like an animated GIF (where the best fix is to simply replace it with a video file), you will have to modify the presentation in PowerPoint itself. However, at least you can find out the cause of a bloated file quickly (sometimes, the cause is what you'd least expect it to be).
However, in other cases where the file format is going to remain the same, you can extract the relevant files from the presentation ZIP, process them locally to reduce the size, and then copy them back. I've used FFMPEG to optimise video clips, and Photoshop to optimise the compression of TIFF, PNG or JPEGs.
Just remember to take a backup of the presentation before you start, in case something goes wrong.
I've had great results using this method in the past - often reducing presentations to a tenth of their size without any noticeable loss in quality.
Another tip - if you're creating a presentation - remember that PowerPoint basically stores a copy of whatever you import or paste. If you make some effort to make sure that what you're adding is already suitably compressed, sized or cropped - then you probably won't have a problem with presentation bloat in the first place.
One such problem cropped up this week - PowerPoint presentation bloat.
We had a fairly simple 40 slide PowerPoint presentation that had somehow grown to 200Mb in size. There was a bit of a panic, because this presentation needed to be made available for 2,000 users to download - so I was asked if I could take a look.
PowerPoint has built in optimisation tools - which will downsample or crop images to save space.
However, I often find that they are either too aggressive (leading to pixelated images) - or perhaps not aggressive enough - making little to no difference to the size of the document.
One tip I've found over the years, is to remember that PowerPoint documents are actually just ZIP files.
If you rename a PPTX file to .ZIP, you can open it in Windows Explorer (please make sure you do this to a copy of the presentation file, not the master file!)
Once you have the ZIP open, look inside ppt/media, and you'll find the raw media assets that form the presentation.
Some examples I've seen that contribute to file size bloat:
- A poorly compressed video file, responsible for 90% of the size of the presentation.
- Poorly compressed JPEG files. A JPEG saved using "best" quality is often unnecessary - especially if it sits behind a colour wash, or has been reduced in size to fit a small rectangle.
- JPEG files that are unnecessarily large. In an office environment, most PowerPoint presentations will be viewed on a 1080p equivalent display. Unless you have a specific requirement to support something larger, any JPEG that is significantly bigger than 1920x1080 is a waste of resources.
- Uncompressed TIFF files (I've seen tiny images occupy 10Mb - enabling compression in Photoshop when saving reduces the size to 100Kb).
- Animated GIFs. I've no idea why people use animated GIFs in PowerPoint presentations - other than it being easy to use them as a slide background image. A poor quality, short animated GIF may well weigh in at 50Mb or more - when converting to MP4 will reduce the size to something more like 1Mb.
- Saving very large photographs as PNGs (yes, I know PNG is lossless - but in most cases, people will never notice the difference)
With something like an animated GIF (where the best fix is to simply replace it with a video file), you will have to modify the presentation in PowerPoint itself. However, at least you can find out the cause of a bloated file quickly (sometimes, the cause is what you'd least expect it to be).
However, in other cases where the file format is going to remain the same, you can extract the relevant files from the presentation ZIP, process them locally to reduce the size, and then copy them back. I've used FFMPEG to optimise video clips, and Photoshop to optimise the compression of TIFF, PNG or JPEGs.
Just remember to take a backup of the presentation before you start, in case something goes wrong.
I've had great results using this method in the past - often reducing presentations to a tenth of their size without any noticeable loss in quality.
Another tip - if you're creating a presentation - remember that PowerPoint basically stores a copy of whatever you import or paste. If you make some effort to make sure that what you're adding is already suitably compressed, sized or cropped - then you probably won't have a problem with presentation bloat in the first place.
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