How do I reduce the file size of a Google Slides presentation?

The main cause of large Google Slides files is large embedded images. Compress images before inserting them: resize to 1920x1080px maximum and compress to under 500KB each. For an existing presentation that's already large, download it as a PowerPoint (.pptx), use PowerPoint's Compress Pictures feature, then re-upload to Google Slides. Google Slides itself has no built-in image compression tool.

What image size is best for Google Slides?

Google Slides uses a 1920x1080 pixel canvas (16:9 widescreen). Images that fill a full slide should be prepared at exactly 1920x1080. Images used as smaller elements (half-slide, quarter-slide) should be sized proportionally: a half-width element needs roughly 960x540. There's no benefit to inserting a 6000px wide photo into a 1920px wide canvas — the extra pixels are stored but never displayed.

Does Google Slides compress images automatically?

No. Unlike PowerPoint (which has a built-in Compress Pictures feature), Google Slides stores images as you insert them. A 10MB photo inserted into a slide remains 10MB in the presentation file. Google Slides doesn't re-compress or resize images on insert. This is why presentations with many uncompressed photos can become very large and slow to load.

Why is my Google Slides presentation slow to load?

Almost always: large uncompressed images. Google Slides must load and render every image in the presentation when you open it. A 30-slide deck with one 5MB photo per slide is a 150MB file. Reducing images to under 500KB each brings a 30-slide deck to 15MB or less — a 10x improvement in load time for remote viewers and in download time when sharing.

What image format should I use for Google Slides?

JPEG for photographs and complex images. PNG for diagrams, screenshots, and images with text. Google Slides accepts both. WebP is also accepted. Avoid inserting HEIC files — Google Slides may handle them inconsistently depending on the browser and operating system.

Compress Images for Google Slides — Reduce Presentation File Size

Google Slides does not compress images — it stores them at whatever size you insert. A 10MB photo stays 10MB in your presentation. Compress images before inserting: resize to 1920×1080px maximum, under 500KB each. For a presentation that's already large, download as PowerPoint, use PowerPoint's Compress Pictures tool, then re-upload to Google Slides.

Why Google Slides presentations get large

Google Slides uses a 1920×1080 pixel canvas. When you insert an image — dragged from your desktop, pasted from a screenshot tool, or inserted from Drive — Google Slides stores the full original file in the presentation. There is no automatic resizing or compression on insert.

A smartphone photo is typically 4–8MB. Insert 20 of them across a presentation and the file is 80–160MB. That presentation is slow to open for remote viewers, slow to download as a PDF, and causes lag when scrolling through slides. None of those 8MB photos look any better than an 8MB photo resized and compressed to 400KB — they're being displayed on a 1920px canvas regardless.

The entire problem is preventable by compressing before inserting. The fix after the fact is more work but doable (see below).

Right-size images before inserting

Google Slides' canvas is 1920×1080 pixels. Image sizing targets:

Full-slide background image: exactly 1920×1080px, under 500KB
Half-slide image: 960×540px, under 250KB
Quarter-slide / column image: 640×480px, under 150KB
Small inline image: 400×300px, under 100KB
Logo / icon: 2× display size as PNG, under 50KB

When you drag an image onto a slide and resize it to take up half the slide, Google Slides doesn't re-store a smaller version — it stores the original and just displays it smaller. The full-size file is still in the presentation. Inserting an already-sized image means the stored file matches the display size.

Compress full-slide images to under 500KB before inserting. For most slide content — product photos, team headshots, stock images — 500KB looks identical to the original at 1920×1080 display size.

How to fix a presentation that's already large

Google Slides has no built-in image compression tool. The workaround:

In Google Slides: File → Download → Microsoft PowerPoint (.pptx)
Open the downloaded .pptx in PowerPoint
Click any image → Picture Format tab → Compress Pictures
In the dialog: uncheck "Apply only to this picture", set resolution to Web (150 ppi) or Email (96 ppi) depending on how the presentation will be used
Click OK — PowerPoint compresses all images in the file
Save the .pptx, then re-upload to Google Drive and open with Google Slides

This process can reduce a 200MB presentation to 10–20MB. The visual difference at presentation display sizes is not perceptible to an audience.

If you don't have PowerPoint: LibreOffice Impress (free, available on Mac/Windows/Linux) has a similar compress feature under Tools → Image Compression.

Screenshots in presentations

Screenshots are a common source of unintentionally large files. A Retina/HiDPI screenshot on a MacBook is 2880×1800px or larger — 3–5MB as PNG. Pasted into Google Slides, that's a large file stored for a screenshot that displays at maybe 600px wide in the slide.

Before inserting a screenshot: crop it to just the relevant portion, then resize to the display width you need (usually 800–1200px), then compress. A 1200px screenshot of a UI at 100–150KB looks perfectly sharp on any presentation display. The 3MB original adds nothing.

Sharing and exporting the compressed presentation

After compressing images, the presentation opens faster for anyone you share the link with. When exported to PDF (File → Download → PDF Document), the PDF will also be significantly smaller — useful if you're emailing the deck or posting it on a website.

For presentations shared as view-only links, the total file size affects how quickly each slide renders when a viewer scrolls through. A smaller file also means cheaper Google Drive storage if your organization has many large presentations. Keeping each image under 1MB is a reasonable rule of thumb for presentations that need to be accessible on any connection speed.

How to Compress Images for Google Slides (and Fix a Slow Presentation)