TinyPNG 2.5 for Mac was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The software lies within Design & Photo Tools, more precisely Converters. This Mac app was originally developed by Voormedia. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe.
From the developer:
Save your compressed PNG files directly from Photoshop. Install the TinyPNG plugin and you will be ready to go. A new menu option will appear in Photoshop from where you can preview, select a folder and save your compressed images.
You may want to check out more Mac applications, such as TinyPNG4Mac, uPic or HappyCoding for Xcode, which might be similar to TinyPNG.