HTML5 Colour Creation

[null]

Hello,
I've been a web developer for many years, but after coming back from a break, I thought it would be fun to play around with HTML5 again.
I am looking for some help however...

I came across this http://slides.html5rocks.com/#css-color HTML5 Presentation, and it gave me an idea:

I would like users to be able to select a colour/shade/hue from a slider, save the data, and finally have it displayed as part of an image.
For example: If you wanted to change the colour of an avatars hair, or the colour of a car bonnet in an online game. The avatar or car would of course be a transparent png image already saved and displayed on the page.

Could someone help me with any ideas on what technology I would be best using for this, or any examples, or suggestions.
Thank you in advance for your help!

I am thinking of using HTML5 for the main page, ImageMagick, php and mysql.

[zcorpan]

Why not use a simple <input type=color> for this, then set the background color of the image onchange, and send the color to the server for saving (submit the form or send over XHR), or some such?