Although the association of well-being (e.g., self-esteem, depression symptoms, and loneliness) with Facebook usage (i.e., number of friends and frequency of use) has been investigated by many researchers, only a limited number of studies have scrutinised Facebook against Instagram use. The aim of this study is not only to address this literature gap but also to explore whether problematic use and well-being differ between Facebook and Instagram users in relation to the number of received “likes” and Facebook friends/Instagram followers, as well as the importance of these “likes” and friends/followers. Sixty-nine Facebook users and 66 Instagram users completed an online questionnaire, including self-esteem, loneliness, depression, and problematic Internet use items. Overall, Instagram users exhibited significantly higher problematic use behaviour compared to Facebook users. Age and importance of “followers” were negatively associated with problematic use of Instagram, whilst only the importance of “likes” was negatively associated with Facebook. The number of Facebook “friends” was positively associated with depressive symptoms, but this was not the case for the number of Instagram “followers”. It is important to note that the number of “likes” was only negatively associated with self-esteem, but there was no association with loneliness. A potential explanation between the differences in the two platforms and well-being might be related to their different functionalities, for example, Instagram is an image-oriented platform that may boost users’ self-esteem through post “likes” but only when the users are strongly connected.