ok... i see what you're running into.
Is the data coming from a database? That way you could use SSRS or Crystal to display the data. You can also control whether or not the viewer of the report is allowed to save the document locally. SSRS comes with SQL Server 2005, and Crystal's Server Services used to come with a licensed copy of the Dev Edition. That way you could completely bypass the PDF to Image issue all together. it would also allow you to create on the fly as needed. Since they are already server services all you need to do is add a link to the report on your website. Sounds like you already have security implemented on your web services, so adding for reports shouldn't be too much more.
Anything more would be beyond my scope, and would need others' input on how to accomplish the task.
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"...and did we give up when the Germans bombed Pearl Harbor? NO!"
"Don't stop him. He's roll'n."
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