If you don't have the original software installed, several online tools can handle the conversion:
ChemDraw supports scripting via CBV (ChemDraw Basic VBA). A sample macro: convert cdx to jpg
If you do not have specialized chemistry software installed, you can use online conversion tools. If you don't have the original software installed,
In ChemDraw, go to Object > Apply Color Scheme > Black on White before exporting. In online converters, look for a "Background" checkbox. go to Object >