Vector Magic is an excellent resource for web designers that would like to convert their raster images to vector images. Having a vector image, allows you to scale it without any bluring. It’s free, it’s online and takes seconds to download your vectorized image on your hard drive (on PNG format). It’s very easy to use and even easier to set your options for getting your desired results. This is one of the smartest applications you will find online.
Not everyone can see the same colours when visiting a website. I have found a great tool online to help you define your stylesheet according to the results. This is only a small part of a usability testing for your website.You can check the usability of colour on your website at: http://colorfilter.wickline.org/
Colorblind Web Page Filter provides different ‘coverage’ filters to choose from.