Either a Rect or bitmap will work.
The problem may lie in the way you are drawing these images to the screen.
If you are drawing to the frontbuffer (NOT backbuffer) only and not using any pageflipping then you should be able to do as you are right now.
If you are using a loop and refreshing the screen by flipping then you need to create and draw to a seperate imagebuffer and copy this imagebuffer to the backbuffer every frame (otherwise the backbuffer and frontbuffer would each contain only bits and pieces of the image).
The problem may lie in the way you are drawing these images to the screen.
If you are drawing to the frontbuffer (NOT backbuffer) only and not using any pageflipping then you should be able to do as you are right now.
If you are using a loop and refreshing the screen by flipping then you need to create and draw to a seperate imagebuffer and copy this imagebuffer to the backbuffer every frame (otherwise the backbuffer and frontbuffer would each contain only bits and pieces of the image).