Gradient Problem

This issue is related to displaying a Gradient image on my desktop machine. I have changed my Destop machine’s (Windows XP) Screen resolution to 800x600 and Color Quality to 16 Bit. With this configuration, if I open a gradient image using MSPAINT application, I am seeing horizontal stripes in it. The gradient color transition is not smooth. But If I try to open the same image using “Windows Picture and Fax Viewer” application, the gradient image display looks smoother. There is no horizontal stripes.

It would be great if anybody can help me in identifying the difference between these two applications. I mean the way they render the image.

Note: The Image which I am trying to display has the following properties:
Res: 800x480, Bit Depth: 24, Horizontal Resolution: 72 DPI, Vertical Resolution: 72 DPI and Frame Count is 1.

Thanks in Advance.

they maybe convert from 16bit to 24bit simply with some interpolation or resize. 565/5551 to 888 you wont see (or hardly) any color banding depedning on the gradient.