Preview has to be one of the most under-appreciated apps on MacOS. It implements so much handy everyday functionality that requires third-party software on Windows. Or did, last time I used Windows (admittedly some time ago).

Yes, really. I use it all the time.

On feature that I use a lot in Preview is to combine pdf's. If you e.g. have a pdf invoice and want to combine that with the corresponding pdf receipt from the bank, I just open the two pdf files side by side in thumbnail view and just drag the pages (thumbnails) I want from one document to the other where I want to place them; rearranging the pages (thumbnails) later if I need to in the same thumbnail view. I am a huge fan of Preview! :-)

Recently learned about Ghostscript and man, it does PDF manipulation really fast. If you find yourself merging PDFs a lot, here you are:

    gs -q -sDEVICE=pdfwrite -o merged.pdf tobemerged1.pdf tobemerged2.pdf tobemerged3.pdf

Ghostscript is similar to ImageMagick in that it does so much that learning to do one specific thing is hard. But that line merged ~300MB of PDFs together in 20s on my M1. Doing that in Preview causes a beach ball.

I installed it with Homebrew, but the project home is yonder: https://www.ghostscript.com/

I love the integration with iOS as well. I was pleasantly surprised to find an option in Preview to use my iPad and the Apple Pencil for my signature. It even popped up some otherwise hidden UI on the iPad to do so.

Preview is the reason my personal, non-gaming computing is still on MacOS and not purely iOS. I'm not even joking.

Preview has an odd selection of functions, though. On one hand it allows you to do plenty of these functions that you mention, but otoh misses on very trivial stuff like "I'd like to make my image a bit larger so I could paste another one next to it".

Isn’t that just on the menu > adjust image size?

I mean, extend the canvas but keep the original image as it is.

Ahh, yes. I have wanted to do this too, and can’t. I suspect Preview isn’t the tool I’m supposed to use, even though it’s the ones I want to use as it doesn’t almost everything I want.

Exactly! It does everything BUT that, and because of that you have to go open a different app.

on windows i find myself bouncing around a lot between pdf viewers, choosing between lightweight but feature sparse options (sumatra) and heavier, more featured programs (acrobat, foxit)

i've never thought about replacing preview.

I always use Preview to "sign" documents due to a lack of a scanner, but I've found in some cases, companies refuse to accept the document because they think it's not actually printed, signed with a pen, and then scanned...

Tools like this will skew and degrade the image in a similar way to a scanner so that it fits this ridiculous requirement

Have you tried signing a piece of paper with a pen and using Preview’s signature scan feature? It creates a very realistic looking signature in my opinion.

Yep, that is what I use. The signature itself looks completely handwritten (because it is), but the companies in question complain that it can't possibly be a handwritten signature because the document didn't look printed and scanned (???). It's slightly ridiculous, but not much I could do other than find a scanner/printer or "comply" with their document formatting requirement

Same. You don't need a camera, you can doodle a signature with a mouse and it's fine. I bought a house this way with no trouble.

It's funny to me to look at a company like DocuSign whose shares surged early on the in the pandemic because they expected a dramatic increase in need for digital signatures and then the price crashed when it turns out that signatures aren't actually useful and we can just live without them.

It is so handy, indeed! I really wish Apple spent some time to make users aware of things like this, which are baked into standard macOS software.

This issue this app attempts to solve is companies that insist on a scanned "wet" signature, and will send it back if it looks like you just pasted in your signature stamp.