Transfer data between asp-pages

[Tobz]

Hi,

I have a asp-page (plot.aspx) that generates an image, like this:

Response.Buffer = true;
Response.ContentType = "image/gif";
npSurface.Bitmap.Save(memStream, System.Drawing.Imaging.ImageFormat.Gif);
memStream.WriteTo(Response.OutputStream);

In another page I use:

<img src="plot.aspx?sql=SELECT ABC&dataname=allCars>
<img src="plot.aspx?sql=SELECT XYZ&dataname=cars2009>

The problem is that I don't like the solution to send the long SQL-query via the querystring. The main reason is that anyone (knowing sql) may abuse this solution.

I would like to discuss solutions to let my page "plot.aspx" know about the sql query, before it "generates" the image.

Any ideas?

/Tobias