Download of XResizer 1.0 for Mac was available 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 Viewers & Editors. This free Mac app is an intellectual property of App2Relax. We recommend checking the downloaded files with any free antivirus.
From the developer:
XResizer helps you easily resize @3x and @2x images into the low-resolution images required for your application. You can just drop your image to the main app window, specify the target folder and wait for the app to create the 2x and 1x images with the right file name and format. It does support .png and .jpg/.jpeg images.
You may want to check out more software for Mac, such as Movie2Shot, TVPaint Animation or Cuadro, which might be similar to XResizer.