Mobile navigation services are becoming more than merely digital maps; many of them include imagery from the street level. The user can benefit from enriching the 2D-map-based navigation with panoramic imagery from the citizen’s perspective, hence gaining an authentic view of the frequent landmarks that urban environments include. In this paper we describe the user-centered design of a mobile street-imagery-based navigation service supporting navigation and exploration of unfamiliar cities. The service was evaluated with a field trial using tourists as participants. The participants used the service freely for the pedestrian navigation tasks that were relevant to them during the trial period. This approach shed light on issues that have not been raised by previous studies on image-based navigation, which have relied on more formal test tasks. The study confirmed that the images help with detecting the destination or assessing the atmosphere of a remote location but brought into focus the real world challenges related to downloading times and positioning accuracy.