I add an image in the imageList i.e a.jpg of blue color. then compile the app and run. the control shows the blue image.

If I delete the image a.jpg from THAT PARTICULAR directory and copy a different image with the same name a.jpg in THAT directory. Windows automatically put the previous (blue) image back. and when run the app the application shows the previous image.

Are you recompiling?

Chances are what's happening is that the image is an embedded resource. It's compiled directly into the assembly. Simply replacing the image file on disk won't change the binary data that's buried inside the compiled code. If you need to be able to use a image file as the source for something in a program, you'll need to write code to read the file and put it into the control(s).

-Peter

Thanx for your reply. Yesterday I got the answer myself that when 1 time compiled, it becomes part of the resource. If we want to display the other image ,we will have to add it in ImageList manually through the design view of the form and replace the previous one.