Hero Web Part Background Image Is Not Resized After Display Scaling Change

What you’re seeing is usually the Hero web part’s responsive cropping rather than the image failing to resize. At 125% Windows scaling, the browser has a smaller effective viewport, so SharePoint may cross a responsive breakpoint and crop the same image differently.

Modern-page images are automatically resized and cropped; a fixed pixel shape isn’t guaranteed across display sizes. In page edit mode, select the Hero slide and use Set focal point so the important area remains visible. It also helps to use an image whose aspect ratio suits the selected Hero layout.

For a clean test, keep Edge or Chrome zoom at 100%, refresh after changing Windows scaling, and compare in an InPrivate window. If the container changes but the image still does not reflow after a full refresh in both browsers, capture the browser build, Windows scale, and screenshots, then ask your Microsoft 365 admin to open a SharePoint Online support case. I’m not aware of a tenant setting that forces a fixed Hero background size.