The great majority of Susanna's paintings depict people, animals and scenes from the countryside around Oporto in northern Portugal. Sometimes she would write the name of the place on the back of the painting, which can be observed on some of her unframed paintings. Sometimes she would sign her painting on the right, sometimes on the left, either with S.R.D. or S R Dockery. Many of the paintings in the possession of her family are not signed or even completed. It is assumed that her finer works were sold both at her various exhibitions and within the English community in northern Portugal. Many of the paintings exhibited below, especially from surviving folders, are simple sketches in preparation for later work and were never intended for exhibition or sale.

Susanna painted for most of her life and hundreds of her paintings and sketches survive. Classification has been made by dividing them into subjects, with a further division into those paintings and sketches that are thought to have been finished whether signed or not, under the heading of 'works', and those that were either not completed or sketches for a subsequent work ('sketches'), although, because of the nature of the material, the decision is arbitory.