Sorry…here’s more info.
I created a Custom Timeline widget, put the code on a test page, and viewed it in the latest release of Chrome. Expanded images were enabled, and the horizontal oriented images in the timeline are getting cropped off on the right edge when you size the page width down for mobile. I manually set the stylesheet for the img.autosized-media class to width 100%, height AUTO, the images gracefully resize responsively without getting chopped.