Slovenia’s polycentric urban development features one large, several medium-sized, and numerous small towns. These small towns vary not only in their urban centre ground plan types but also in the subjective image of these centres, as perceived by their users. The presence of public open space correlates with and impacts the image of the urban centre. The research question of this paper examines the relationship between the morphological characteristics of urban centres and the presence of public open spaces, the connection between various types of public open spaces and the image of the urban centre, and the role these spaces play within the urban context. The research methods are a survey questionnaire, statistical analysis, and spatial analysis. The latter enables an accurate inventory of public open spaces. It also highlighted differences in the function, type, and extent of these spaces across the urban centres. The results for the two towns selected for the paper are compared with the findings from the survey questionnaire, which was carried out in 33 towns. This study reveals that a town with a complete medieval and modernist ground plan is better equipped with public open spaces designed for pedestrian use (Škofja Loka = 3.07, N = 76) than one with an incomplete modernist ground plan (Grosuplje = 2.23, N = 47), resulting in a more positive image (Škofja Loka = 3.56, N = 79) compared to the other town (Grosuplje = 2.41, N = 49). A well-equipped centre with public open space (paved surfaces, promenade, and square) is vital for a positive urban image and contributes to the town’s identity, as confirmed by residents.