Most current approaches to image retrieval rely on either keywords (that will be evaluated against mainly manually provided metadata) or dedicated query objects (query-by-example). In our work, we consider query-by-sketch, an approach that allows users to specify (parts) of the image they search for on the basis of a color and/or edge sketch. Particular attention will be given to user interfaces and devices, partial matches, invariances in terms of rotation, displacement, scale, etc.