I suspect you have overlooked the feature, if you tried that many libraries, not 100% sure though. For example, you can use:
http://canvasjs.com/html5-javascript-scatter-point-chart[
^],
http://demo.huihoo.com/rgraph/docs/scatter.html[
^].
I believe you can find a lot more if you expand your search properly. First of all, it does not have to be MVC or even ASP.NET. It's absolutely clear that you can generate appropriate Javascript data and invoke graphics from your ASP.NET application. Moreover, this is much better to stay away from
strong coupling with any particular server-side technology and better for performance.
[EDIT]
If you have to, you can always make a derived work from the Javascript library, to add images. Javascript libraries are all open-source, by definitions.
And, by the way, I would like to warn you against using proprietary (and non-open) libraries, as it can lead to
vendor lock in:
http://en.wikipedia.org/wiki/Vendor_lock-in[
^].
—SA