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

https://images1-focus-opensocial.googleusercontent.com/gadgets/proxy

Parameters:

• 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:

URL:

https://images1-focus-opensocial.googleusercontent.com/gadgets/proxy?url=https%3A%2F%2Ffiles.czm.io%2Ff%2Fblog-istanbul.jpg&container=focus&resize_w=300&resize_h=300&refresh=2592000

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

URL:

https://images1-focus-opensocial.googleusercontent.com/gadgets/proxy?url=https%3A%2F%2Ffiles.czm.io%2Ff%2Fblog-istanbul.jpg&container=focus&resize_w=650&refresh=31536000

Quirks

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.