Your image is CMYK instead of sRGB and most browsers are not good at displaying CMYK images. You probably want to convert it to sRGB instead. The next version of Magick.NET will include a new method to do this easily, you can take a look at the changesets below to see how I implemented this:
https://magick.codeplex.com/SourceControl/changeset/8c19c37c227d128b2534bdbec086f6fa32e45ed6
https://magick.codeplex.com/SourceControl/changeset/9ae6d33c222dd8f77976017b575fd357f46da354
https://magick.codeplex.com/SourceControl/changeset/8c19c37c227d128b2534bdbec086f6fa32e45ed6
https://magick.codeplex.com/SourceControl/changeset/9ae6d33c222dd8f77976017b575fd357f46da354
