Lossless vs recompression mode?

[nekohayo]

I realize this might look a bit like something "out of scope" given the app name, "pdfslicer", but it's a pretty common usecase and it would be fantastic if we could find this feature in your tool as a "one-stop shop": the ability to recompress PDFs to a lower target filesize when needed (but default to lossless pages manipulation if not specified by the user).

The usecase is primarily for when you need to email a dozen PDF files in a single email to some bureaucratic organization that can't deal with external links (ex: nextcloud links and such) but would also have a mail server that would bounce your emails if they weigh too much. I've had such a scenario today where I had to attach 13 documents and one of them was 8.5 MB in filesize, so I was nervous about the resulting 15 MB+ email, and would have preferred to be able to use PDF Slicer to optimize the filesize of the images in one or two of those PDFs (if we could somehow use MozJPEG as the encoder, you'd already gain 10% efficiency in addition to being able to recompress, while getting fully standard and compatible JPEGs as the output).

Some other apps similar to PDFslicer, such as "pdftricks", attempt to offer this feature, but I'd much rather have everything in one single GNOMEish app like PDFslicer, than to use 3-4 different apps for handling PDF assembly and compression.

It could be a GtkSwitch toggle in the UI somewhere maybe? Ideally with a target filesize, but I reckon that might be hard to calculate; if so maybe a quality percentage and DPI encoding settings could do the job.