Downloading Resizo 1.3 for Mac from the developer's website was possible when we last checked. We cannot confirm if there is a free download of this app available. This software for Mac OS X is an intellectual property of Vistanita.
The software lies within Design & Photo Tools, more precisely Viewers & Editors. We recommend checking the downloaded files with any free antivirus. The following version: 1.3 is the most frequently downloaded one by the program users. This software is compatible with Mac OS X 10.7 or later.
From the developer:
Easily resize multiple images at once. There are 5 types of resize: percentage, fixed width, fixed height, fixed size and fit to size. The resized images can be saved as JPEG or PNG.
It also has presets feature which allows you to save your favorite customizations for easy access.
Resizo is retina display and Mountain Lion ready.
You can download free trial version on http://www.vistanita.com/resizo/
You may want to check out more software for Mac, such as iPodEditor, OnTheAirCGServer or Flickr Widget, which might be similar to Resizo.