I believe we got this sorted out through your email support case, but I'll post the answer here in case anyone else stumbles on this topic. The Browse button on the main Screen Saver tab is for looking for screen saver (.scr) files, in case DisplayFusion didn't find them automatically.

To use the DisplayFusion Photos Screen Saver, first select it in the drop-down list to the left of the Browse button, and then click the "Settings" button to the right of the Browse button. That will open the settings for the DisplayFusion Photos Screen Saver, and in there, you can choose the folder of images to use, along with a few other settings.

Thanks!