The MB web timeline jams photos together unpleasantly (Before screenshot). I wanted them spaced (After). I use Safari on Mac so I made a stylesheet and pointed Safari to it. CSS:

.post_text img {margin-top: 1.5em;
background-color: #ffffff;
box-shadow: 5px 5px 5px gray; }

Before: photos jammed together. After: photos spaced and with shadow. Safari Advanced Preferences screenshot showing selected stylesheet.