Manu:
I'm not quite sure what you mean by points having an "image" on the X-Axis. If you would like to plot something without the points being shown, then you can set the "Point style" to "None" under the "Plots" tab.
If you're having some problems with the actual rendering of the control (i.e. the control is drawing on the X-Axis), then I would suggest that you contact our e-mail or phone support to continue this discussion. You can reach our email support at http://www.ni.com/ask or our phone support at 1-800-IEEE-488.
Good Luck!
Chris Wood
Applications Engineer
National Instruments