Facebook users unknowingly reveal personal information that may help attackers to perpetrate malicious actions. In this paper, we show how sensitive age information of a given target user can be predicted from his/her online pictures. More precisely, we perform age inference attacks by leveraging picture metadata such as (i) alt-texts automatically generated by Facebook to describe the picture content, and (ii) picture reactions (comments and emojis) of other Facebook users. We investigate whether the target’s age affects other users’ reactions to his/her pictures. Our experiments show that age information can be inferred with AUC of 62% by using only alt-texts and with AUC of 89% by using combination of alt-texts and users’ reactions. Additionally, we present a detailed analysis of spearman correlation between reactions of Facebook users and age.