can I delete previews folder in iPhoto? What is the Effect/

Previews are smaller JPEGs of the edited versions of your photos created in your System Photo Library for sharing with other applications using the Media Browser.

And I am seeing in this folder all editing results returned by photo editing extensions.

When I tried to delete previews from this folder, the Photos for Mac app just recreated them. I would not rely on that, however, that Photos can fix it, if you willfully modify the library. It will do no good to try to remove the previews. It will just slow Photos down,

if you need to save storage on your SSD move the Photos Library to a portable external drive. That will give you plenty of storage for your photos.

Do not remove anything - the instructions posted in these forum hundreds of time are Very simple and abundantly clear - NEVER make any changes to the structure of content of the iPhoto (or Aperture of Photos) library - there are no user serviceable parts in it

the SQLite database is very complex and unless you are a SQL expert you can not make any changes - any changes you make are likely to cause problems and dataloss

You need to move your iPhoto library to an external disk - it must be formatted Mac OS extended (journaled), connected with a fast wired connection like FireWire, Thunderbolt or USB, always available prior to launching iPHoto and not be used as a TimeMachine backup volume

Quit iPhoto and drag the iPhoto library to the EHD then hold down the option key while launching iPhoto and select the new locations

LN

I'll join the chorus: never make any changes to the iPhoto Library with any app except iPhoto. You risk massive dataloss if you do.

If space is an issue move the Library:

Make sure the drive is formatted Mac OS Extended (Journaled)

1. Quit iPhoto

2. Copy the iPhoto Library from your Pictures Folder to the External Disk.

3. Hold down the option (or alt) key while launching iPhoto. From the resulting menu select 'Choose Library' and navigate to the new location. From that point on this will be the default location of your library.

4. Test the library and when you're sure all is well, trash the one on your internal HD to free up space.

Regards

TD

You want to move the pictures from one Library to another? You can do this easily with iPhoto Library Manager

https://www.fatcatsoftware.com/iplm/