Flotcharts (http://www.flotcharts.org/) plugin to enable custom images for each point.
Image parameters should be added to the points object in options, like so:
points : {
show: true,
radius: 15,
image : {
path: 'img/', // Base path to the images you want to use
base: 'day.svg', // Base image you want to use in case one is missing
images: icons // An array of image names corresponding to the plot points
}
}