ImageOptim is an awesome open source (free) image optimizer. I recently started using it and wanted to let all you know about it.

Optimizing your images with ImageOptim will reduce your image file size while maintaining the same quality. What is does is strip off all the unnecessary data that is included with in the image. For instance it compresses by removing unnecessary information, like EXIF tags, file comments and color profiles.

For certain people like myself, optimizing images is very important. If this is your first time at AppDucate, go take a look around. You’ll quickly notice that there are a multitude of images everywhere. Each and every featured image (the large images at the top of each post) is processed in ImageOptim before being uploaded to AppDucate. This helps the webpage load faster which makes everyone happier.

ImageOptim supports JPEG, PNG and GIF files (including GIF animations). For most of the images I’ve tried, I’ve seen a saving of around 10-20%; that may not sound like a lot but over the course of a week that’s gigabytes of saved bandwidth.


The interface (GUI) is very simplistic, which is something I love about it. All you have to do is drag and drop images into ImageOptim. It will then automatically go to work compressing the image and then will show you what percentage of space you just saved. Unfortunately there is no progress bar showing the overall progress,you just kind of have to wait until the rotating loading image finishes. This isn’t a huge issue, however it would be a nice feature to have.

It’s also very fast at compressing… depending of the files being compressed. For instance, compressing the above featured images took around 1 second, whereas compressing my 3200 x 2000 desktop wallpaper took 8 seconds.

imageoptim review mac

In its settings there are a few options you can go through to customize the output of the pictures. One thing to take note of is the “Backup original files before saving”. By default this is turned off. If you don’t have the backup option selected then any image you drag into ImageOptim will be overwritten when it’s finished compressing. If you’d like to compare, or keep the original image then make sure you have the backup option checked. The original image will be renamed to imagename.png~.

There are also other settings you can change by going to the different tabs in its preferences. The “PNGOUT”, “OptiPNG”, “AdvPNG” and “JPEGOptim” tabs allow you to change the optimization strength. Lowering the optimization setting will reduce the time it takes to compress, but the resulting file size will not be as compressed.

Download: ImageOptim