Marz, to begin with, the resolution of your pics is too wide. It forces us to have to scroll to see it all. You should use the standard format we always post game pics with (two 320w images=640w). You can still cram six images on there, I suppose, but constrict your width to 640 pixels so it fits.
IE has a bug that they will never fix where it randomly thinks pics are bmp format, so you just have to live with that.
The reason Opera probably still thinks the image is a PNG file is more than likely because the PNG file is still in your cache. I am using Opera and it tells me that it's a GIF file. That should have been the first thing you thought of, really.
Over the Net was released in Europe by Genias, in the US by Merit, and was developed by Dardari Brothers. Its release date was 1990.
At Codetapper's site, there is a Rob Northen interview that lists most of the RNC games (at least the ones Rob remembers or the ones that were created in-house). I can't believe you didn't know this was here, considering how immersed you appear to be in the whole WHD genre.