Research on the multimedia effect in testing indicates that static representational pictures (RPs) and, potentially, dynamic RPs that further subdivide the picture into segments may support students' mental processing. This might be especially relevant for mathematical word problems that pose high mental demands in a multistage solution process. Existing studies further indicate that contrary to expectations of practitioners, static decorative pictures (DPs) do not improve students' affective state. It is unclear if dynamic DPs that decorate each segment of a word problem better meet these expectations. In our preregistered online experiment that involved 308 students in a 3 × 2 mixed design, we manipulated word problems regarding three visualization conditions (RPs vs. DPs vs. text-only), and two kinds of dynamics (static vs. dynamic). As expected, static and dynamic RPs increased response correctness, metacognitive ratings, and satisfaction compared to text-only. Besides this replication and extension of the multimedia effect in testing, dynamic RPs did not outperform static RPs in direct comparisons, however. Both RP conditions did not extend the time-on-task compared to text-only. As expected, static DPs did neither increase response correctness nor metacognition nor satisfaction compared to text-only. However, dynamic DPs were also unable to increase satisfaction compared to text only. Additional analyses that took the item position into account unveiled that the time-on-task in dynamic DP items aligned to that of text-only items over the course of the experiment, so that the students might have ignored dynamic DPs over time. Finally, we conclude implications for using these visualizations in digital assessments.