The earliest picture postcards in the UK date from 1894 as it was not until 1st September of that year that the post office allowed postcards published by others to be posted.
From 1895 onwards, a size of 4.75 ins x 3.5ins was adopted for postcards. These cards were known as Court Cards. The address was written on one side and the reverse had a small picture leaving sufficient space to write a message.
In 1902 the post office changed the rules so that the picture could take up the whole of the front of the postcard. The message and the address both appeared on the back. The message on the left hand side and the address on the right. From around September 1902 publishers printed postcards with a line dividing the back.