Not to nitpick or anything, but the first example on the site shows a bar chart with the example code being:

<img src="//api.chartspree.com/bar.svg?Foo=1,1,2,3,5">

However the actual embedded code for the example and the resultant chart is:

<img src="//api.chartspree.com/bar.svg?Foo=1,1,2,3,6">

My immediate reaction to seeing the wrong chart being displayed for some example code was that your system just didn't work properly.

As this is the first thing anyone sees when visiting the project, it might be a good thing to change.