NoiseNinja 2.2.0 for Mac could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The application lies within Design & Photo Tools, more precisely Viewers & Editors. We recommend checking the downloaded files with any free antivirus. The following versions: 2.3 and 2.2 are the most frequently downloaded ones by the program users. The actual developer of this free software for Mac is PictureCode LLC.
From the developer:
Noise Ninja is the most effective and productive solution for removing noise and grain from digital photographs and scanned film images. It is a must-have tool for anyone shooting in low-light or fast-action situations -- including news, sports, wedding, and event coverage -- where high ISO photography is required and the resulting noise compromises the image.
You may want to check out more Mac applications, such as I Can Animate, PhotoGPSEditor or ImageBuddy, which might be similar to NoiseNinja.