Understanding the city to make it smart

Understanding the sentiment of people is a process that may be useful when transforming a city into a smart city. A recent trend is to exploit social media data to infer people sentiments. While many studies focused on textual data, few considered the visual contents. In this paper we investigate whether the images available in the Instagram platform can be useful to understand people sentiments. Through an experimental assessment and two different validation methods, we observed that although the use of images in sentiment analysis can be useful to have insights about people sentiments, the use of Instagram images may be slightly misleading.