how to improve pixel maps resolution?

Is there any method to improve the resolution of 2D diagram (xy axis + curve) saved into .bmp file?
The primary graph size is 900x900 pixels, but I want to get the resolution of saved bitmap of at least 1800x1800 pixels.
Is it possible?

Best regards

This is a ogl coding forum, isn’t this a little OT?

Photoshop anyone?
For suggestions on algorithms I would advice you to try

If you just want to render the graph and save it, use a anti-aliased pbuffer.

[This message has been edited by roffe (edited 07-10-2003).]

I just would like to know is there any solution of this problem in OGL (e.g. pixel maps manipulations).