Changing the image on the screen form by clicking the button

[Eugene Lutsenko]

Can anyone tell me how to change the image displayed on the screen form by clicking the button on this form? Let this image is formed by pressing the button, and written to a file, but does not appear in the process of formation, and this is displayed in the screen form, as a file. In principle, because of you I learned to change the background on the timer interrupt. Maybe this can be done in a similar way?