Big, eye-catching images are one of the easiest ways to make a presentation look professional. But they come with a catch: every high-resolution photo you drop onto a slide adds weight to your file. If you add to many images and videos without compressing them then you end up with a presentation that is slow to open, painful to email, and prone to stuttering or freezing on presentation day.
The good news is that PowerPoint has a built-in tool that fixes this in seconds. You do not need any extra software, and you do not need to be technical. This guide walks you through exactly how to compress a photo or image in PowerPoint, how to reduce the MB size of your file, and how to do it step by step without the risk of ruining the way your images and overall presentation looks.
A 10-second quick win
If you only have one or two oversized images, the fastest fix is to swap the file type. Photos saved as PNG or TIFF are often much larger than they need to be. JPEG is the most efficient format for images.
To convert one or two images, just right-click the image, choose Save as Picture, and select JPEG as the file type. Then delete the old image, insert the new JPEG, and save. The only exception is images that need a transparent background (such as cut-out logos), which should stay in a PNG format.
For everything else, the proper tool is PowerPoint’s compression feature which we will guide you through below.
How to compress images in PowerPoint: step by step guide
These steps work in PowerPoint for Microsoft 365, PowerPoint 2024, 2021, 2019 and 2016 on Windows. Mac steps follow further down this article.
Step 1: Click on an image
Click once on any photo in your presentation to select it. As soon as you do, a new tab called Picture Format appears at the top of the PowerPoint ribbon.
If you want to compress only specific images rather than every photo in the file, hold down the Shift key and click each one you want to include.
Step 2: Open the Picture Format tab
Click the Picture Format tab in the ribbon. Look for the Adjust group on the left-hand side.
Step 3: Click Compress Pictures
In the Adjust group, click Compress Pictures. A small dialogue box will open with a few options. This is where the magic happens.
Step 4: Choose how widely to apply it
At the top of the box you will see a tickbox labelled Apply only to this picture.
Untick this box to compress every image in your whole presentation at once. This is what you want most of the time, and it is the quickest route to a smaller file.
Leave it ticked if you only want to compress the image (or images) you currently have selected.
Step 5: Delete cropped areas
If you have cropped any images, PowerPoint quietly keeps the bits you cropped off, just in case you want them back later. Ticking Delete cropped areas of pictures permanently removes that hidden data and can shrink your file significantly.
Only tick this if you are confident you will not need to undo your crops, because once it is done you cannot get those areas back.
Step 6: Choose your resolution
This is the most important choice. Under Resolution, you will see several options measured in PPI (pixels per inch). The lower the number, the smaller the file:
HD (330 ppi)
Highest quality, largest file. Only needed for high-definition displays or detailed imagery.
Print (220 ppi):
Use this if you plan to print your slides as handouts.
Web (150 ppi):
The sweet spot for almost all presentations. Sharp on screen and projectors while keeping the file size down.
Email (96 ppi):
The smallest file size. Ideal when you need to email the deck, though quality drops noticeably.
For a deck that will be presented or shared on screen, Web (150 ppi) gives you the best balance of quality and size. If your only goal is to email the file and quality matters less, choose Email (96 ppi).
(Note: if some options are greyed out, the image has already been compressed once. You cannot compress back up to a higher resolution than the image currently has.)
Step 7: Click OK and save
Click OK to apply the compression, then save your file (File > Save, or Ctrl + S). The compression is only locked in when you save, so do not skip this step.
To see the difference, check your file size before and after by going to File > Info, or by looking at the file in your folder. It is not unusual to cut a file by 50–80%.
How to compress images in PowerPoint on a Mac
The process is almost identical:
- Click an image to select it, then open the Picture Format tab.
- Click Compress Pictures.
- Choose your Picture Quality (resolution) from the dropdown.
- Choose All pictures in this file or Selected pictures only, and tick Delete cropped areas of pictures if you wish.
- Click OK and save.
You can also reach it from the menu bar via File > Compress Pictures.
Why your PowerPoint file gets so big
When you insert a photo, PowerPoint stores the full original image, often far more detail than a screen will ever display. A single photo straight from a phone or a stock site like Shutterstock or Unsplash can be several megabytes on its own. Stack ten or twenty of those across your slides and your file balloons.
Here is the key thing to understand: a screen does not need all that detail. A full-screen image only needs to be around 1920 x 1080 pixels to look crisp on most displays. Anything beyond that is invisible to your audience but is still being carried around in your file. Compressing simply throws away the detail you cannot see, so your slides look the same while your file gets dramatically smaller.
Expert Insight: Change the default setting so PowerPoint compresses automatically
You can tell PowerPoint to compress images automatically every time you save, so you never have to think about it again.
On Windows, go to File > Options > Advanced, scroll to the Image Size and Quality section, and set the Default resolution to 150 ppi. On a Mac, go to PowerPoint > Preferences > General.
Do not forget to compress your videos as well
Images are usually the main culprit, but embedded videos can be even heavier. To compress them, go to File > Info, then click Compress Media and choose a quality level. For most presentations, Internet Quality (or HD 720p) is more than good enough.
One caution from our team – compressing media can strip out embedded subtitles or separate audio tracks, so check those still work afterwards.
Quick tips to keep your files small from the start
The easiest compression is the one you never have to do. A few habits go a long way:
- Use JPEGs for photographs and reserve PNGs for graphics that genuinely need transparency.
- When downloading from stock sites, choose a smaller size rather than the largest available.
- If an image only fills a quarter of the slide, it only needs a fraction of the resolution of a full-screen image.
- Run a compression pass before you send or present, as a final check.
Summary
Compressing images in PowerPoint takes about thirty seconds and can transform a sluggish, oversized file into one that opens instantly, emails easily, and runs smoothly when it counts. Select an image, open Picture Format, click Compress Pictures, untick Apply only to this picture, choose Web (150 ppi), and save. That is genuinely all there is to it.
Need your presentation to look the part as well as run smoothly?
Compressing images keeps your file a healthy size, but a truly memorable presentation comes down to design. At Presentation Experts, we are a London-based team of PowerPoint specialists who design bespoke, results-driven presentations for brands including Sainsbury’s, Unilever and the NHS. Whether you need a full deck designed from scratch, a template built for your team, or a tired presentation given a new lease of life/redesign, then get in touch for a no-obligation chat with our team by filling out our contact form below.
