On many websites that use images, you can click on the image to have it “pop out” over the webpage, displaying a larger image that’s easier to read. SharePoint Online pages now support this Lightbox feature when you put an image on a page using the Image web part. Here’s how it works…
On this page, I have a screen capture that is somewhat on the small side. In order to pop out this image using the Lightbox feature, I simply click on the image:
The image now shows up in its full size, overlaying the web page and dimming it out. To get back to the web page, just click on the X in the upper-right corner:
One Minute Office Magic 