Image vanish when scroll

Please help:

i am creating drawing in panel using gdi+. But when i scroll or resize the image is just vanished or just half of them vanished according to the area that i scroll.

Any idea?
thanks

Without seeing some code its going to be practically impossible to help you, because there are many variables that could be causing your problem. You say your drawing in the panel, but you don't say if your drawing to a back buffer or directly to the panel. Is drawing being called from a sub, or is being called as part of the OnPaint event. How/ what are you scrolling and resizing.