You create an image list by calling the ImageList_Create function. The parameters include the type of image list to create, the dimensions of each image, and the number of images you intend to add to the list. For a nonmasked image list, the function creates a single bitmap large enough to hold the specified number of images of the given dimensions. Then it creates a screen-compatible device context and selects the bitmap into it. For a masked image list, the function creates two bitmaps and two screen-compatible device contexts. It selects the image bitmap into one device context and the mask bitmap into the other.
The initial size of an image list is determined by the size values you specify in ImageList_Create. If you attempt to add more images than you initially specified, the image list automatically grows to accommodate the additional images. In ImageList_Create, you specify the amount of images by which the image list can grow.
If ImageList_Create succeeds, it returns a handle of the HIMAGELIST type. You use this handle in other image list functions to access the image list and manage the images. You can add and remove images, copy images from one image list to another, and merge images from two different image lists. When you no longer need an image list, you can destroy it by specifying its handle in a call to the ImageList_Destroy function.