www.wysiwygwebbuilder.com

I have been building a site for a client who has only MAC/iPad & iPhone, While it is still in the early stages, she complained that the icons I was using for social media are pixelated, and she was right. The issue is that iOS devices seem to display with a much higher resolution and for example if you have a 40x40 icon, what you should do is make it 80x80 but within your page, resize it to 40x40 if that is the size you want.

A much better detailed explanation is here if you are interested:

http://bit.ly/1e9E7Se

Alternatively you can use a script like this:

http://imulus.github.io/retinajs/