Many studies have demonstrated that illustrating expository science texts with images that are interesting, but irrelevant for understanding the causal relations underlying scientific phenomena, can cause seduction effects, which can reduce understanding from text. The term "seduction effects" refers to the influence that images are thought to have on readers, seducing them away from deeply processing important information. The present study explores whether images relevant for instructional goals may also show some seduction effects. In this study, the presence of photographic images negatively impacted understanding compared with the presence of relevant animations or instructing students to sketch a drawing during reading. However, the results showed that both photographic images and relevant animations could lead to illusions of understanding, whereas sketching did not. The results suggest that even images that are relevant for instructional goals may sometimes result in seduction effects that deceive readers when judging their own understanding.