Summary by @rschroll: The Xpdf version of pdftoppm doesn't support the -png flag, but Xpdf does provide a pdftopng command that we could use instead. It currently has problems on Windows, but we should support it as soon as those problems are fixed.
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Light Table version: 0.6.5 (on Windows 7 x64)
Binary version: 0.8.4
LiTeX version: 0,0.7
pdftoppm version 3.04