only PDF output is supported when using the ADF

[launch pad sucks]

The scan utility scans the pages from the adf to single png-files but then forces the conversion to pdf.
While this is clearly done by design, I see no good reason for it.

The patch attached adds support for skipping this conversion and keeping the png files.
It is only a few lines and quite simple and should be self-explaining.

I would be really happy this was reviewed and implemented in a somewhat less hacky way.
If you do, there is no need to give any credit to me for it. I don't care about that.

BTW: It really sucks to have to register and verify an email address just to report a bug.

[Bill Yikes (yik3s)]

Just wanted to mention this bug still exists >10 years later in version 3.22.10.

[Bill Yikes (yik3s)]

Question regarding the patch: is this patch purely a convenience? If `pdfimages` is used to unpack the PNG files, is the result the same or does the patch in any way avoid a lossy conversion?