If you are a web developer, you might be already working with color codes for CSS and web design. Windows does not have any default option to select a the color from other images and websites. Plastiliq PixelPicker is a useful freeware color picker tool that gets the pixels color under your mouse pointer on the screen and translates it into a number of different color formats. You can simply drag the mouse pointer on to any window or image on screen and it selects the color for each pixels available.
Once you have select an image, you can zoom in to larger extend so that you can select the color by a pixel. It supports colors in various formats which includes RGB, ARGB, HTML, CMYK, HSL, HSV/HSB, HEX, HEX with alpha, Decimal and Decimal with alpha.
You can also make the app stay on top, so that you can get the color codes easily and quickly. There is a built in clipboard support by which you can simply select the color by clicking on the color box inside the app.
The app works on Windows XP, Windows Vista and Windows 7.