ImageOptim

ImageOptim is a front-end (GUI) for set of tools for optimisation of PNG and JPEG images.

Optimisation makes files smaller (in terms of disk space) by finding optimal compression parameters and by removing unneccessary information, like file comments, EXIF tags and color profiles.

Note: Now requires OS X 10.9 or later.

• Added experimental Guetzli optimizer
• It's off by default (enable in Preferences), because it's very slow: 1 minute + 200MB RAM per megapixel; it is normal for a large photo to take 10 minutes and gigabytes of memory
• It's ineffective on JPEGs with quality 85 or lower; it's best to create JPEGs with 100% quality for running Guetzli on them
• Guetzli does not support color profiles, so only use sRGB
• Running Guetzli on the same image twice is not recommended, as it will decrease quality more than it reduces the file size; if you need smaller files, disable Guetzli, and enable Lossy mode instead
• Added new languages: Arabic, Finnish, Slovak, Ukrainian