This is currently on our feature request list, so I've added your vote to it. We'll be sure to let you know if/when we're able to implement it in the future.

In the meantime, you can achieve this with a bit of creativity and the latest DisplayFusion 8.0 Beta, available here: https://www.displayfusion.com/Download/Beta

After updating to the beta, try these steps out:

• Create two Wallpaper Profiles, one for InterfaceLIFT and one for Vladstudio.
• On the DisplayFusion Settings > Functions tab, click the "Download Scripted" button, double-click the "Randomly Load a Wallpaper Profile" script, and click OK to save it. Click Apply to save the DF Settings.
• On the Triggers tab, add a new rule like the one in the attached screenshot.
• Click OK to save the DF Settings and wait to see if the wallpaper changes on the timed interval set in the Trigger rule

Thanks!