Programming question: odd behavior of CSS with a GIF image

I have a GIF image of a form…let’s say it’s a tax form, with lines and boxes for the user to put information in.

I’m printing text in the lines and boxes on the form using CSS, and specifying the position in pixels to start printing the data. So, for example, I say something like “Start printing the first name at pixel 200 from the top, 50 from the left.” I’m using absolute positioning.

Here’s where it gets odd. On three of the four test machines I have, running different screen resolutions, everything lines up.

On the fourth machine, the text does not line up with the boxes when displayed on the monitor, but it does line up if I choose “Print Preview” or actually print to paper.

The screen resolution I’m using on that fourth machine is 1280x1024, IE 6.0.2800.1106. I don’t think the browser version is causing it, as one of my other machines runs exactly the same version. Nor do I think it’s the resolution, as I’ve tried changing the resolution and still get the same problem.

Anyone have any ideas what might be causing this, and more importantly, how to fix it?

Thanks very much,

Len