Template:Mbox/styles.css

th.mbox-text, td.mbox-text {  /* The message body cell(s) */ padding: 0.25em 0.9em;    /* 0.9em left/right */ } td.mbox-image {               /* The left image cell */ padding: 2px 0 2px 0.9em; /* 0.9em left, 0px right */ } td.mbox-imageright {          /* The right image cell */ padding: 2px 0.9em 2px 0; /* 0px left, 0.9em right */ }