Graph grammars provide a useful formalism for describing structural manipulations of multi-dimensional data. We briefly review theoretical aspects of graph grammars, particularly of the embedding problem, and then summarize graph-grammar applications. Currently graph grammars are used most successfully in application areas other than pattem recognition. Widespread application of graph grammars to picture processing tasks will require research into problems of large-scale grammars, readability of grammars, and grammatical processing of uncertain data.