>>>See https://docs.microsoft.com/en-us/windows/win32/api/_gdiplus/ for all stuff available, if the GDI+ class of VFP misses something, just add it. The chance of incompatible classes in later versions is zero. :)
>
>I'll see what I can scavenge from the excellent Foxypreviewer as well, since it has had report watermarking for years.
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>One thing did occur to me: using vector images yields better quality in a report, but it's probably quite easy to erase a watermark from a vectorized image compared to a png or bmp that weaves it into the other pixels. Might have to change back to images!

Erase from the printed result? Or from what? Is this watermark functional for the customer or just some copy protection for you?
For the first consider to add something functional - an QR code with print info and some sort of certification for example. UUID printed in the corner of the reports to identify the report, certificate from customer. something like that, where removing alone would destroy the integrity.