The majority of multimedia learning studies focus on the use of graphics in learning process but very few of them examine the role of graphics in testing students' knowledge. This study investigates the use of static graphics versus animated graphics in a computer-based English achievement test from a cognitive load theory perspective. Three hundred and three 7th-grade students were randomly split into two groups and given the test questions either with static graphics or with animated graphics accompanied with text. Students' response time, response accuracy, self-reported ratings on cognitive load and secondary task approach were used to measure their cognitive load. Findings revealed that animating graphics increased the response time and secondary task scores of the students but did not have any significant effect on their test success. Furthermore, no difference was observed in self-reported cognitive loads. The relationship between the four different cognitive load measures was also examined in the study. No direct relation was found between self-reported ratings and secondary task scores. On the other hand, self-ratings and response accuracy were found to be more sensitive to intrinsic cognitive load, whereas response time and secondary task measures were found to be more sensitive to extraneous cognitive load in our testing environment.