This paper reports on students' ability to decode mathematical graphics. The findings were: (a) some items showed an insignificant improvement over time; (b) success involves identifying critical perceptual elements in the graphic and incorporating these elements into a solution strategy; and (c) the optimal strategy capitalises on how information is encoded in the graphic. Implications include a need for teachers to be proactive in supporting students' need to develop their graphical knowledge and an awareness that knowledge varies substantially across students. Examples from the six graphic languages, their perceptual elements and encoding techniques are shown in the appendix. (Contains 3 tables and 2 footnotes.) [For the complete proceedings, "Shaping the Future of Mathematics Education. Proceedings of the Annual Conference of the tional Mathematics Education Research Group of Australasia (33rd, Freemantle, Western Australia, Australia, July 3-7, 2010)," see ED520764.]