ColorQuality property

Only available for ImageList objects.

Read/Write at design time

Specifies the color quality for an image list. It can be one of the following values:

0 - Auto (default)
1 - 4-bit
2 - 8-bit
3 - 16-bit
4 - 24-bit
5 - 32-bit

You can download an ImageList simple project by clicking here.