Resdroid 1.0 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. This free Mac application is an intellectual property of Rimbunesia.com. The application lies within Developer Tools, more precisely Webmaster Tools. We recommend checking the downloaded files with any free antivirus.
From the developer:
Resdroid lets you easily resize your image assets to targeted resolution sizes (ldpi, mdpi, tvdpi, hdpi, xhdpi, xxhdpi, and xxxhdpi). You just drop all your images into the app, set the mdpi size, and you may check the "make grayscale" button or change the tinted color of the resulting image.
You may want to check out more Mac applications, such as Browsealoud, solr or joomla-, which might be related to Resdroid.