Forwarded Image to PDF and PDF to image without reencoding

[Gibtnix]

Hello,

I recently came across IrfanView's feature of converting Images to PDF (select your images in Thumbnails and use multipage PDF conversion option in right click menu) and its counterpart of extracting single-page images from a multi-page document (PDF or TIFF, even though I'm only interested in PDF here).

According to my tests, there is no option to simply import / export the respective images without reencoding them. Therefore, I would like to highly recommend this as an additional feature.

I find multi-page PDFs particular useful for scanned documents, which I prefer encoding as JPGs as scans are unavoidably lossy and it saves a significant amount of space in comparison with PNG or even uncompressed formats like BMP. However, if I want to modify the document somehow (e.g. add or remove a page or change something), I extract the existing images and would like to re-create the PDF without changing the pages that remain the same. Re-encoding all pages during import/export is an unnecessary quality loss.

Currently, I'm using img2pdf (create PDF from a set of images) and pdfimages (extract images from PDF) for lossless conversions in both direction. I think it should be relatively easy to offer the same options in IrfanView.

[JendaLinda]

IrfanView is an image viewer in the first place, not a PDF editor. The PDF functionality there is a bonus - quick PDF viewing in preview quality and conversion of arbitrary images to PDF format. Image editing is done in BMP format internally in IrfanView. Specialized tools often do a better job as you mentioned. I would stick with them.

[Bhikkhu Pesala]

You can use lossless compression using the img2pdf plugin or the new PDF plugin. Choose which to use in Settings, Plugins.

[Gibtnix]

@JendaLinda Yes of course, sticking with img2pdf and pdfimages is possible, still I would appreciate the PDF import / export options without re-encoding. Therefore I just wanted to propose this feature.

@Bhikkhu Pesala: Thanks for pointing out. I tested the new PDF plugin export option already, still lossless compression does not copy the original image but re-encodes it using a lossless encoding. This unluckily increases the file size by a factor of 20x during my tests, thus not an option. I didn't know there is a img2pdf plugin. I installed the plugins using the installer and I think it is not included (i.e. available somewhere else). I did not find it, do you know where to download the img2pdf plugin? Would like to give it a try...

[JendaLinda]

I can see that it might be useful to be able to edit one picture in a multipage file without touching the other pictures in the file. If you wish to suggest such feature, feel free to contact the developer, Irfan Skiljan, see Help -> About IrfanView.

[IrfanUserGuyxyx]

I am not concerned with the reencoding, but I have used IV to edit one page in a multipage file many times, but you have to save each page you change before you go to another page.

[Gibtnix]

JendaLinda Sure I can try this - but does Irfan not already consider the discussion here? As IV is not open source, I thought here is actually the right place to suggest new features to the developers (i.e. Irfan himself), or isn't it?

[JendaLinda]

This is only user to user forum.

[Gibtnix]

Alright, then I maybe try to mail to Irfan directly. Thanks anyway!