Imagination is a virtual expression that puts things in alternative perspectives to create new experiences and establish different value possibilities. Few studies on learning photography by vocational school students use the Self-Reporting Scale of Photographic Imagination. To supplement this deficiency, this paper explores the imagination of the creative process in photography and develops a Scale of Photographic Imagination. The researcher conducted a survey on 700 students from vocational high schools in Taiwan with a pre-test and a formal test of the scale. The item analysis and the exploratory factor analysis (EFA) on the pre-test suggest that the scale contains in its structure four factors: Photographic Technique, Choice of Things, Image Fabrication and Combination, and New Value Image. The analysis of each factor is good. The confirmatory factor analysis (CFA) on the formal test also suggests goodness-of-fit of the four-factor structure.