Google's authentication-less, on-the-fly image resizing service

Did you know Google runs a free and open image resizing service? I certainly didn’t.

While lazily poking around the Google+ HTML I found an interesting thing: for resizing post images on the fly, G+ uses an open API endpoint. That might come in handy at some point in the future when prototyping this or that, so jotting down some notes felt like a good idea.

If you know more about this API, let me know, please! (See the sidebar for options.)

A word of warning before I progress: I’ve spent ~45 minutes on both my experimentation and this here write-up, maybe an hour. You’ve been warned.

Base URL


  • url: original image URL
  • container: must be “focus” ¯\_(ツ)_/¯
  • refresh: time (in seconds) to cache it on G’s servers
  • resize_w: width in pixels
  • resize_h: height in pixels

You can either specify both resize_* parameters or just one.

An example

Let’s resize that big 5831×1644 panorama picture I took in Istanbul a while ago.

Make it square, 300x300px and cache it for 30 days:

Resized image, 300x300px


Make it 650px wide, keep the aspect ratio and cache the result for a year:

Resized image, 650px wide



At least in Chrome, opening the URL in the browser will force the download of a p.txt file (which is actually a JPG). Putting the URL in an <img> tag is fine, tho. Or just use curl to save it locally.

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Carlo Zottmann @czottmann