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Image Optimization Services

By Jason Grigsby

Published on October 2nd, 2014


Responsive images are landing soon and many organizations are looking for ways to resize images. Thankfully, there are a number of startups, established companies, and open source solutions for image optimization.

I’ve pulled together a spreadsheet of the image optimization services to make it easy for people to explore their options.

For example, GD and ImageMagick are available on many platforms and you could build your own service using them. Many CMS tools have built-in image resizing tools.

I focused on services and software that provided a level of abstraction (e.g., you can ask for image resizing via a URL) or were specifically focused on responsive images.

The spreadsheet has a column for detection to indicate whether or not the image resizer tries to automatically detect what size of image to request or deliver.

Detection comes in two forms. One is using the user agent string to look up information in a device database. The other uses JavaScript to either find the same information or find the exact size of the image element in the page.

With the responsive images specification landing in browsers soon, I’m not sure if detection is desirable. The benefit of srcset and sizes is letting the browser choose what source is best.

Many of the image services offer services that can crop, filter, and otherwise manipulate images. Some even add things like focal point or facial recognition.

As long as you’re centralizing images processing, you should try to find a service that will compress them as much as possible and provide other performance benefits such as caching and CDN support.

If I were evaluating services, I would be looking for these things, but comparing image compression is tough because it is a balance of raw file size and image quality the requires a judgment call.

When I published this spreadsheet originally, I got a lot of people asking for column to compare price. I resisted adding it until recently. And I only report on whether the service is free or paid.

Comparing prices in the spreadsheet is pointless. Every service that charges varies pricing based on the volume of images. The prices will change in the future, and I don’t want to maintain that information. And the services are different.

I encourage you to explore the services themselves. Some are quite reasonably priced and the expensive ones offer a ton of features.

So take a look at the list of image resizing services. If you see something that is missing, please let me know.

I hope you find this useful.


Luca Passani said:

Thank you for mentioning the WURFL Image Tailor, Jason. We do rely on the HTTP request (mainly the User-Agent string) to determine an optimal image size for the user’s device, but that’s only to endear lazy webmasters to us. More proactive front-end programmers can use URL parameters to resize the picture to whatever works for them, possibly after they have used a custom bit of JavaScript to fine tune the resizing parameters to what makes the most business sense for their application.

Will Norris said:

err, actually I think atmos/camo is just an image proxy (GitHub uses it to remove mixed content warnings)… it doesn’t actually do any manipulation or resizing.

Jon Arne Sæterås said:

Thanks for the overview, Jason.
Whether detection of optimal image size is a desired feature or not, is a great question. Respimg empowers the browser to make a very qualified decision of what is the most optimal of the provided sources. I trust browsers will do a very good job at this in the near future. This leads me to conclude that services relying on JavaScript to do detection, really are replaced by the browsers ability to do the same natively. A much better option.
For server side detection I can still see several use cases because it’s simply convenient to have the functionality available, for a sensible default or fallback if nothing else.
Will be interesting to see how web editors and developers ACTUALLY will be using respimg 🙂

Paolo said:

Hi, thank you very much for this spreadsheet. Is it possible to add new services?
I’m working on an image resizing service with a focus on ease of use and developer friendliness. At the moment we are in private beta and we are working on a responsive solution.

stevesun said:

This is very useful list. It saves me a lot of time to learning the most useful feature an image hosting service should have. I wonder if it is possible to add ImageS3 ( to the list, this is a open source project I am working on, this is an image hosting service which enables developers to manage and resize images for all mobile and web apps in one place. Recently, I have released a working version 0.2.0.