Automatically Resize Images in Google Docs with Apps Script

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Images can quickly break the layout of a Google Doc.
If you’ve ever pasted screenshots, charts, or photos into a document, you’ve probably had to manually resize each one so it fits nicely on the page.

Good news: Google Apps Script can automate this completely.

In this post, you’ll learn how to use a simple Apps Script function to resize all images in a Google Doc to 50% of their current size—saving time and keeping your documents clean and consistent.

Why Automate Image Resizing?

Manually resizing images is:

  • Time-consuming
  • Inconsistent
  • Easy to forget when working fast

Automating image resizing is useful when:

  • Creating tutorials or documentation
  • Working with lots of screenshots
  • Cleaning up imported or copied content
  • Preparing docs for printing or sharing

With Apps Script, you can fix this in seconds.

What This Script Does

This script:

  • Loops through all inline images in the active Google Doc
  • Reads each image’s current width and height
  • Resizes the image to 50% smaller
  • Preserves the original aspect ratio

It works safely and can be run multiple times.

The Apps Script Code

function resizeImagesToHalf() {
  const doc = DocumentApp.getActiveDocument();
  const body = doc.getBody();
  const images = body.getImages();

  images.forEach(image => {
    const width = image.getWidth();
    const height = image.getHeight();

    image.setWidth(width * 0.5);
    image.setHeight(height * 0.5);
  });
}

How to Use the Script

  1. Open your Google Doc
  2. Click Extensions → Apps Script
  3. Paste the code into the editor
  4. Save the project
  5. Run resizeImagesToHalf
  6. Approve permissions (first run only)

Once it runs, every image in the document is resized instantly.

Adjusting the Resize Percentage

You’re not limited to 50%.
Just change the multiplier value:

Desired SizeMultiplier
75%0.75
60%0.6
40%0.4

Example (resize to 60%):

image.setWidth(width * 0.6);
image.setHeight(height * 0.6);

Important Notes

  • This works on inline images only (the most common image type)
  • It does not affect drawings or positioned images
  • Each run resizes images based on their current size
  • Safe to use in production documents

When This Is Especially Useful

  • Cleaning up long technical documents
  • Normalizing screenshots pasted from different sources
  • Automating Docs workflows
  • Teaching Apps Script automation examples

Final Thoughts

Google Apps Script is incredibly powerful for small automations like this.
What takes minutes (or hours) manually can be done in a single function call.

If you’re working with Google Docs regularly, small scripts like this can dramatically improve your workflow.