This article discusses the collection of photographs in the archive collection of Sweden's Gypsies (Sw. Sveriges zigenare) at the Nordic Museum, created by the folklorist Carl-Herman Tillhagen. Many of the photographs originate from the so-called inventory of “Swedish Gypsies”, part of the state “Gypsy investigation”, performed in 1954–1956. The aim is to critically analyse Tillhagen’s creation of this collection to gain a greater understanding of the collection and its background. We explore how and in what context Tillhagen compiled the collection and added written information to the photographs. We also place Tillhagen in a century-long anthropological, and colonial, tradition of field works aimed at creating knowledge about “the other” and the use of photography in this practice. In doing this, we pay attention to Tillhagen’s field work methods and role as a “gypsy expert”, his way of using photography and his composition of the collection. The collection can today appear to be both strange and prejudiced, while it also contains rich information of various kinds, e.g. about Roma’s living conditions as well as the normative ideals of the majority society, and about the role of folklore research and the folklore archives in collecting information on national minorities. By producing knowledge about the background of the collection and circumstances surrounding its origin we contribute to the possibility of using its photographs with a critical eye for new interpretations and new knowledge.