Add Image functionality is not working under Page Background and Wallpaper section in Format Pane

Could not reproduce it in my side as far as my test. Both new format pane and old format pane work fine in Power BI Desktop.

Please try to update to the latest version of Power BI Desktop to check it again(December 2021 2.100.785.0)

Best Regards,
Community Support Team _ Yingjie Li