: Image optimization API

Optimized : 122KB
Original : 384KB
68% saved
Optimized : 122KB
Original : 351KB
65% saved
Optimized : 89KB
Original : 289KB
69% saved
+ images already optimized !

New features !

Compression optimization & EXIF stripping

Since version 1.4.21 (feb. 2017), JPEG optimization has been improved with an average additionnal 5% weight reduction. Moreover, EXIF data are by default removed (see API page).

2 billion pictures optimized !!!

We've now reached in Feb. 2017 the second billionth pictures optimized, and still for free :) New servers will arrive this month for still better performances :)

Official Wordpress Plugin

Thanks to Maecia Agency, a new Wordpress plugin has been released for in June, 2016. Please welcome Image Optimizer.

1 billion pictures optimized !

In May 2016, has proudly reached the first billionth Pictures optimized ! And it keeps going on !

API Endpoint has changed

Since March 2016, the endpoint has changed. Please upgrade your scripts from to The old endpoint will be deprecated on 30th Sept. 2016

Customizable image quality factor.

Optimization at 92% Optimization at 75%

Optimization at 92% (82 Kb) and at 75% (54 Kb)

You can now specify your compression level for JPG pictures ! Go to API page for more informations.

What is reSmush it ? is a FREE alternative to Yahoo (which discontinues on March 2015). This tool provides an online way to optimize pictures size via a documented webservice. is 100% compatible with old Yahoo API.

Supported CMS and Tools

How does this works ?

Webservice call

For a standard call, with a JSON response, you just have to call this url and provide the image attribute like one of these options below :

The webservice will return an array of informations about the compressed image (see API page for more informations)


This tool is based on several well-known algorithms such as pngquant, jpegoptim, optipng.
It allows to reduced until 70%-80% the size of uploaded pictures.

Yahoo alternative

You can replace your existing solutions that were running under with that The webservice is fully compatible with the Yahoo's distribution, and it will return more informations about your conversion.

Just replace the old non-working url by the webservice url : and everything will work great!

Replacement webservice tested with Drupal's ImageAPI Optimize module (dev version) and with Wordpress Image Optimizer plugin.


PNG comparison

Non optimized PNG image Optimized PNG image with

Original picture (left) 186,1 Kb, Optimized picture (right) 69,6 Kb : gain 63%