MacOS – How tocon? files work and how to create your own

Hallelujah! I figured it out. Okay, so first thing I did was create a new account, as suggested by another answer. The problem did not occur in there, so clearly the problem was limited to my account. I then went into Safe Mode into my account. The problem did not occur as well. So clearly something was loaded in normal mode but not in safe mode that was causing the problem.

While in safe mode, I then cleared the caches (in Terminal, using sudo mv /Library/Caches ~/Temp/ and the same for ~/Library/Caches). Problem solved! I've had other problems as well in Finder so perhaps this will fix this as well. I'm curious as to why using Onyx to clear the User caches didn't clear these as well, but anyway, from what I've read online it seems like getting rid of these two folders is safe. Also, Time Machine never backs up ~/Library/Caches (but it does back up /Library/Caches), so that's reassuring.

In addition, while this post was made in 2003, it still applied to my situation and this was what convinced me to clear my Caches folders.

You can change the default size in the view options panel:

The sizes of icons are also stored in .DS_Store files that override the default setting. You can delete them by running sudo find / -name .DS_Store -delete, but it also resets other display options and removes Spotlight comments. The changes aren't always picked up until you quit and reopen Finder.