History of border-image

Adjusted second live sample

Fixed live samples

Replaced 'border-image-repeat' examples by different 'border-image' examples

Added Gecko compatibility note related to bug 837211 and bug 1259345

Replaced relative URLs in examples by absolute ones (so that you can view them in CodePen and JSFiddle)

Clarified and corrected Firefox compatibility note

Added missing closing bracket

Adjusted Firefox/Firefox Mobile compatibility note regarding the uplift of changes to Gecko 49 in bug 1264809

Added compatibility notes related to bug 1264809, bug 1284798 and bug 1284797

Enhance description.