Some images from these works by Roger Bacon have been digitized:
Roger Bacon, Specula mathematica (Frankfurt, 1614). The copy in the History of Science Collections at the University of Oklahoma Libraries is bound with Perspectiva (Frankfurt, 1614).
Roger Bacon, Epistola de Secretis Operibus (Hamburg, 1618).
Roger Bacon, Thesaurus chemicus (Frankfurt, 1620).
Roger Bacon, Opus majus (London, 1733).
Roger Bacon, The Opus majus of Roger Bacon (Bridges editor), (Oxford, 1897).
Primarily the images from these works consist of title pages and frontispieces.