Welcome to the wild and uncivilized world of non-color management on the web. This is what happens when you don't take your precautions. Long story short as I'm in a bit of a hurry:
Your first example is what a ProPhoto file looks like without color management. To avoid this, always convert to sRGB for web use.
The second example is what an sRGB file looks like without color management (sRGB is the Save For Web default). Closer, but still not corrected for your display. Only a web browser with full color management would display this entirely correct (Firefox).