ColourChimp is a software for gathering screen colours, comparing them and editing them a breeze so that it is really easy to get the hex for the colour you are after. You can then copy the appropriate representation (ARGB, RGB, HSV, CMYK) of the colour to your clipboard to copy direcly into the XAML code.

Gather
1. Region of interest (Ctrl+R)
2. Full screen
3. Windows (list active windows in desktop)

Colour space
1. ARGB (Alpha, Red, Green, Blue)
2. CMYK (Cyan, Magenta, Yellow, Key)
3. HSV (Hue, Saturation, Value)

Grid modes
1. Size colurs to grid
2. Columns

Other options:
1. Keep application in foreground
2. Use maximum alpha on previews

Populate
1. Reds
2. Greens
3. Blues
4. Cyans
5. Magentas
6. Yellows
7. Achromatic grayscale
8. Pre-defined Presentation Framework
9. System colours

Colours Option:
1. Add current
2. Populate
3. Sort
4. Filter
5. Selective removal (Ctrl+D)
6. Remove last (Ctrl+Z)
7. Clear all (Ctrl+C)

You can Import the colours from image files, such as *.bmp,*.gif, *.jpg, *.png and *.tif, program can export as a 24-bit Bitmap (*.bmp) file.

The license of this software is Freeware, you can free download and free use this image utility software.