This study employs an eye-tracking experiment with Instagram posts to explore how (political) actors can capture users’ attention with mobilizing messages and encourage political participation. Grounded in the Elaboration Likelihood Model (ELM), the study investigates both top-down (low vs. high involvement) and bottom-up factors (neutral vs. activating image; political vs. non-political source) in influencing political participation. The findings indicate that issue involvement is a significant predictor of low-threshold participation (liking, sharing), while task involvement significantly predicts high-threshold participation ([intention to] purchase). Additionally, visual attention significantly affects high-threshold but not low-threshold participation. These results contribute to understanding attentional mechanisms in political mobilization and provide strategic insights for designing effective visual social media campaigns.