In this particular example, the meaning is implying thoughtfulness or thought provoking. :-)

I found the referenced text online, from the book about Manga. Reading the whole paragraph, which talks about a"limited print run", meaning only a few copies were produced, leads me to believe that the book had a physical, reflective, mirror-like frame to make the point that the reader needed to be reflective when looking at the art. So I think that "reflective" here means both literally and figuratively "reflective".