Downloading WallBot 2.3 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. The software belongs to Theming Tools. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. This free software for Mac OS X was originally created by Stoican Silviu Marian.
From the developer:
WallBot is a minimalistic menu bar app that can change your desktop wallpaper as you prefer. Your desktop background photo will automatically change after a specific time interval. You can change the category and the background photo at any moment. In order to change the desktop picture automatically, it is recommended to set the app to launch at system startup.
You may want to check out more software for Mac, such as App for the milk, Desktop Saver or LiquifyDesktop, which might be similar to WallBot.