Most compatible file types when saving images/pictures to Photos app across devices

cmaiaj wrote:

1) Which file types/format(s) (i.e., .jpg, .jpeg, .png, etc) are most compatible so that

images/pictures are saved to the Photos app and to iCloud so that they are available across Apple devices?

All are equally compatible.

2) Specifically for Mac, what is the purpose of/reason for the “Pictures” folder and how can I adjust the settings to automatically save photos/images to the Photos app and iCloud to be available across Apple devices?

The Pictures folder contains the Photos Library used by the Photos app and can also contain Pictures used by other apps that do not go into your Photos Library. For example the Photo Booth Library is also available there.

3) How, if possible, can I adjust my settings so that screenshots are saved directly to the Photos app?

After you take the screen shot, you should see the thumbnail in the lower right of your Mac where you can click that and the Share button with the selection Add to Photos. It does also save it in the location specified such as the Desktop, but is a shortcut to add it to your Photos Library too. Not exactly what you are looking for, but it works.

4) Please provide the correct settings to completely disable the “on my iPhone” and “on my iPad” accounts on my devices so that all devices sync only with iCloud, never locally to just the device (same devices and operating systems as mentioned above).

Not sure which apps your are referring to here. Photos are either in iCloud or not. For an app like Notes, go to Settings > Apps > Notes, and you will see a toggle for On My iPhone/iPad that can be turned off. On the Mac you would open the app such as Notes, then choose Settings where you will see the same option.

5) How can I remove additional duplicate photos dispersed throughout my Photos library that have not been identified as duplicates via the new “duplicates” feature (same devices and operating systems as mentioned above)?

The duplicate check takes time to run in the background and when a duplicate is detected, then you will see the duplicate album to review. If you add a duplicate photo, it is not going to immediately show up as a duplicate. You will want to have a device plugged in and using WiFi overnight to ensure that the algorithms have had sufficient time to detect the duplicates. The duplicate detection is not perfect and while some photos make look the same, they may be slightly cropped, different file type, different compression, different file size, etc where it may not be identified as truly a duplicate photo. In some cases, manually reviewing is the best method and some third party apps have resulted in unexpected photo loss. The Apple algorithms are conservative on duplication to prevent that from happening.

cmaiaj wrote:

1) Which file types/format(s) (i.e., .jpg, .jpeg, .png, etc) are most compatible so that

images/pictures are saved to the Photos app and to iCloud so that they are available across Apple devices?

• HEIC is the high efficiency standard, and it's recognized by all Apple devices. Some other OSs are a bit iff on their ability to use heic, though.
• jpg and jpeg are exactly the same and are recognized by every device on the planet.
• png allows for transparency, but it sometimes isn't accepted by some apps.

2) Specifically for Mac, what is the purpose of/reason for the “Pictures” folder and how can I adjust the settings to automatically save photos/images to the Photos app and iCloud to be available across Apple devices?

Like most folder, the Pictures folder does whatever you want it to. It's a handy place to put pictures. It is the default location for the Photos Library that holds the pictures that are viewed and edited in the Photos app. But, like most things, if you are rebellious and want to put the Photos Library somewhere else, that's OK. It is not OK to put the Photos Library in iCloud Drive or other places not directly connected to the Mac.

3) How, if possible, can I adjust my settings so that screenshots are saved directly to the Photos app?

Everything to know about screenshots:

Take a screenshot on Mac - Apple Support

Take screenshots or screen recordings on Mac - Apple Support

4) Please provide the correct settings to completely disable the “on my iPhone” and “on my iPad” accounts

on my devices so that all devices sync only with iCloud, never locally to just the device (same devices and operating systems as mentioned above).

When you are using iCloud, Finder won't let you transfer pictures to "From My Mac." If you already have pictures like that, they need to be re-imported so they can be handled by Photos properly. Pictures in From My Mac can't be uploaded to iCloud Photos, and they may get lost in the transition,

5) How can I remove additional duplicate photos dispersed throughout my Photos library that have not been identified as duplicates via the new “duplicates” feature (same devices and operating systems as mentioned above)?

Photos will find exact Duplicates, and it often finds pictures that look the same and differ only in resolution or other aspects. You have to be careful when "merging duplicates" to be sure that you don't really want to keep them both.

If you want more control then you can use the trusted 3rd party app PowerPhotos ($35) which does loads of other things. Or use  PhotoSweeper ($15) which is cheaper but does less. Other "Duplicate Finders" and "Mac Cleaners" may really mess up the Mac-- stay away from them.