I had the similar problem. I tried to put my pictures in status map also (although they were in gif format), and figured out there was a problem in a path where I've put my pictures. Put them where is defined by the configuration in cgi.cfg under "physical html path". And if you put them where is defined, but with one directory deeper (in your specific directory), then in hostextinfo.cfg you shoud define the path like this:
I don't think it is a converter problem, althogh you could try the gif images if everything else fails.