I find the slideshow speed too fast and would prefer a 15-30 second duration.
I'm looking for a solution for Monterey in particular but I think this applies to Big Sur as well, and maybe Ventura and beyond.
I know the relevant plist is at /System/Library/PrivateFrameworks/Slideshows.framework/Versions/A/Resources/Content/EffectDescriptions.plist and I believe the key that needs changing is mainDuration in the JustASlide key. The terminal command below would work if the plist could be made user-writable.
sudo /usr/libexec/PlistBuddy -c "set ':JustASlide:mainDuration' 10" /System/Library/PrivateFrameworks/Slideshows.framework/Versions/A/Resources/Content/EffectDescriptions.plist
I've found answers listed below helpful but I'm so far unable to fathom how to apply either of the potential solutions to the making the root filesystem writeable to this problem. I also don't want to risk not being able to use Filevault.
Working on the hunch that versions of the plists in /Library/ would override the ones in /System/Library/, I tried recursively copying /System/Library/PrivateFrameworks/Slideshows.framework/ to /Library/PrivateFrameworks/Slideshows.framework/ and changing the destination plist, but this had no effect.
OS X Mavericks screensaver changes pictures too quickly: How do I slow it down?
How do I change the image display duration in the Catalina screensavers?
Can I mount the root (system) filesystem as writable in Big Sur?
