Williamson exhibited regularly at the Liverpool Academy and was a close friend of the Liverpool-based artist William Lindsay Windus (1822-1907). He painted in a Pre-Raphaelite style for some of the 1860s.
The brilliant colouring and detailed depiction of the sheep in ‘Morecambe Bay from Warton Crag’ were probably inspired by the work of Pre-Raphaelite painter William Holman Hunt (1827-1910). This painting may have been directly influenced by Hunt's picture 'Strayed Sheep' (now in Tate gallery).
In later years Williamson's style changed completely and he made impressionistic, misty watercolours.