photos from mac running catalina to older mac running high sierra

Export photos in a selected format

You can export photos so that you can import and work with them in other apps. You can also export a Live Photo as a still image. You can choose the size and format for the exported photos.

1. In the Photos app  on your Mac, select the item you want to export.
2. Choose File > Export > Export [number] Photos.
3. Click the Photo Kind pop-up menu and choose the file type for the exported photos.

• • JPEG creates small-size files suitable for use with websites and other photo apps.
  • TIFF is a lossless file format that works well for transferring photos between computers and apps.
  • PNG is another lossless file format popular for web images.

1. Click the File Name pop-up menu and choose how to name the exported files (this step is optional).
2. You can name your exported files using the titles you’ve given them in Photos, their filenames, or a filename numbered sequentially. If you choose Sequential, you can specify text to appear before each number (for example, Birthday - 1, Birthday - 2, and so on).
3. Click the Subfolder Format pop-up menu and choose how to divide the exported files into folders.
4. For example, if you export photos from several different days, you can have Photos export each day as a subfolder named after the day. Choose None to export the photos as individual files without subfolders.
5. Click Export.
6. Choose where to save the exported photo files, then click Export.

Tip: If you’re signed in with your Apple ID and have iCloud Drive turned on, you can export photo files to iCloud Drive, then access them from any Mac, iPhone, iPad, or Windows PC set up to use iCloud Drive. See Use iCloud Drive to store documents.

Not sure what the deal is with TM, but Backups deserve theor own druve... or two if the data is important. :)

Hi Joshe. First, I’ve never used Time Machine to backup or software based photo management systems because I find my own “hands on” approach better. I organize my photo images into folders by year and categories. (Folder Example: Hilton Head 2017 Travel Photos) I’ve always owned an external hard drive for backup. As I add new photos, or update files, I simply attach computer to backup device and DRAG AND DROP the folders or files! Easy! Once you have all your data on backup device, attach the backup to your other computer, no matter what version, and Drag and Drop! You are only moving files. This past year I was recommended to purchase a Western Digital drive from Amazon that can fit in my hand or pocket. I got the 2 TB size (See photo) My life can fit in my pocket! You should have all your main data files backed up on this. Note, I had been confused because info people posted about this WD drive said I needed to install a software to use it. Not true! I just plugged it into my MacBook and simply dragged my Documents folder over. Life is sometimes amazingly simple and direct.

If you are trying to use a photos library from Catalina to import your photos to an older

photos library/ Photos app in an older macOS then you can't do this.

You can go forward but not backwards.

You would need to export your images from the Catalina photos library

to a folder and then import them to the Photos app in the older OS.

You may find that not all metadata and any edits done in the newer version of Photos

is not imported to the oder version of Photos on the older mac.

Migration Assistant is not very good at going backwards.

Using Time Machine for two macs can cause trouble, a Time Machine Drive

as part of its first folder structure uses folder called Backups.backupsdb,

so that is fine if you are backing up one mac, but if you introduce another

mac then Time Machine will wonder what the heck is this.

If you want to back up two macs to one external drive then

partition the external drive to two Volumes, one for the

new mac and one for the older mac.

And then in System Preferences> Time Machine

in each mac you can select the partition/ Volume

you want to save your backups to.

The Photos app keeps your images in a photos library which is normally in your Pictures folder,

it is called Photos Library.photoslibrary.

You cannot import the photos library from a mac using a newer OS to a mac using an older OS.

The only way to do this is to open Photos on your Catalina mac and export your images to a folder(s) on the

Desktop or on an external drive.

In Photos you could select the category Photos in the left column, click Edit

and then Select All, click on File> Export, you will be asked to Export *** images, this will allow you to export

them as a single file type (jpeg, tiff or png) and include any modifications made. Or you can choose to Export

as unmodified originals, this will preserve the original file information and file type but will not keep any

modifications you have made.

The problem with Edit> Select All in your case is you have amassed 90GBS of images, this will take a long time,

a lot of space which you may not have and will probably fail.

Think up a strategy to Export items in smaller chunks in some sort of logical order, perhaps you have organised

your images into different Albums or Projects, so while exporting you can designate a folder for each so that gets

transferred to Photos on your older mac. Try doing this one folder/ project/ album at a time so you can assess if

the way they are exporting and then importing into the older version of Photos is reflecting how they are displayed

in Photos on the newer mac.

Once you are ready to transfer the exported folders to your older mac then use either a USB stick, or an external HD,

or connect the macs by ethernet cable.

In the older version of Photos click on File Import and then import the folders/albums/projects in a logical order

so you know that the Photos apps on each mac will look the same.

But as I say experiment a little bit by bit rather than going for a big dump of images.

Frankly it would be easier building a new extension and dealing with builders.

Any luck yet?

Well I have given you some thoughts and instructions in my earlier post.