If you can load both images on the UIR when you develo the application (i.e. they are not too big) you could use a picture ring control associating the values 0 (False) and 1 (True) to them according to your needs. Simply using SetCtrlVal (panel, control, 0 (or 1)) will display the right image and hide the other.
If you need to load images at run-time you can load them using InsertListItem (panel, control, index, "image_pathname", value). Again, assign 0 or 1 according to your needs.
If you prefere to have only one image loaded in memory at a time, you can use a simple picture control instead of a ring and load the desired image with DisplayImageFile command.
