Previous research shows that portrayals of the beauty ideal in the media lowers appearance satisfaction. The Tripartite Influence Model assumes that external factors influence the individual to internalize this ideal and compare with it, which contributes to lower appearance satisfaction, but it does not explain short-term changes in individuals. The short-term effects of the media are explained by the Differential Susceptibility to the Media Effects Model, which postulates that the effects caused by the media on an individual are determined by their's characteristics but also that these characteristics can change them. Based on the integration of the propositions of the two models, the Model of Media Effect of Instagram Content on Appearance Satisfaction was designed. It hypothesizes how content on Instagram can influence adolescents' state appearance satisfaction. The research was conducted with high school students in Croatia using the ExpiWell application, through which data on Instagram content and state appearance satisfaction was collected 4 times a day for 10 days. The obtained data were analyzed by multilevel modeling. The results show that depictions of people do not significantly contribute to state appearance satisfaction, but the average effect is stronger in adolescents with higher appearance evaluation. The results indicate that depictions of people do not significantly contribute to social comparison. In cases where adolescents compare themselves to a person they have seen, they report significantly lower state appearance satisfaction, and this effect is stronger in younger adolescents. The results show that neither depictions of peers nor depictions of celebrities contribute significantly to state appearance satisfaction, but the effect of depictions of celebrities is stronger in adolescents with lower appearance evaluation. The results indicate that depictions of people on Instagram alone don't, but social comparison has a significant effect on adolescents' state appearance satisfaction. The knowledge obtained provides a basis for further research into the effects of using social media on the daily functioning of adolescents and indicates the importance of including adolescents in the preparation of research.