The 6.2.8 version of WaiFu2x for Mac was available to download on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The program lies within Design & Photo Tools, more precisely Viewers & Editors. According to the results of the Google Safe Browsing check, the developer's site is safe. Despite this, we recommend checking the downloaded files with any free antivirus software. This free software for Mac OS X is a product of Yi Xie.
From the developer:
WaiFu2x is an application that scales images on Neural Networks. The tool can scale and/or denoise images, GIFs, and videos using Convolutional Neural Network (CNN). This utility is the iOS Core ML/MPSCNN implementation of waifu2x. The app supports an unlimited number of imported images, GIFs, and videos.
You may want to check out more Mac applications, such as TurboCAD Mac Designer, DropImageURL or Polaris, which might be similar to WaiFu2x.