Background Pictorial warnings are superior to text-only warnings for cigarettes. However, little research has examined the impact of cigar warnings among youth, including image characteristics that may increase their effectiveness.Methods We conducted an online within-subjects experiment September-October 2022 among N = 680 youth ages 15–20 who reported little filtered cigar or cigarillo (LCC) use or susceptibility to LCCs. Participants evaluated six FDA-proposed warning statements with one of six randomly assigned images selected from an earlier study phase. We double-coded warning images based on presence/absence of image features, including wound depiction; internal organ depiction; smoking cues; and symbolic/metaphoric representations; and assessed level of graphicness. Outcomes were perceived message effectiveness (PME), negative affect, and believability for each warning. We used linear mixed models to assess associations between image characteristics and outcomes, controlling for participant characteristics and warning statements.Results About half of the sample identified as a woman/girl (56.2%) and White (56.3%). Warning images with a wound or an internal organ (vs. not) resulted in higher PME, negative affect, and believability (ps < 0.05). Warning images that were “very” or “moderately” graphic versus “not” graphic elicited higher negative affect ratings but lower believability ratings (ps < 0.05); with no significant difference for PME. Symbolic representations (vs. not) and smoking cues (vs. not) resulted in lower PME and negative affect (ps < 0.05).Conclusions LCC warnings with images depicting internal organs or wounds of the health effects may enhance the effectiveness of warnings, which could hold promise for deterring LCC use among youth.