From Yvonne King:

Re: Mostly-male book images may reduce girls’ science scores (April 23): A long time ago when I was an undergraduate (late 1970s), we undertook some research on the effects of introversion and extraversion when it came to using mental imagery to aid short term memory recall. This was published in the Journal of Mental Imagery because the research came up with some odd result which seemed to indicate that the sex of the researcher actually affected the results when correlated with the introversion and extraversion factor and this was more important than the ability of introverts and extroverts to use mental imagery.

This would seem to support the evidence provided by the above research and suggests, as the research on science books does, that the sex of your teacher and the sex of people in images shown, really do have an affect on educational outcome.