How Do I Regenerate Thumbnails in Photos

Photos does not have individual First Aid procedures like iPhoto does. It only has one procedure, Repair Library. Launch Photos with the Command+Option keys held down and repair the library. That may or may not fix your thumbnails. You'll just have to try it and see.

Note: If your iPhoto library was a reference library Photos will not convert it correctly.

Your iPhoto app is still on your hard drive in the Applications folder. It was not deleted from the hard drive, only removed from the Dock. It can still work with 10.10.3 if it is iPhoto 9.6.1. If not but is some version of 9.x you can try to get it from the App Store by following the instructions posted by Terence Devlin in this post:

Terence Devlin

Apr 14, 2015 11:21 AM

Re: Is Iphoto gone ? i want it back!

in response to Johannes666

Recommended

Go to the App Store and check out the Purchases List. If iPhoto is there then it will be v9.6.1

If it is there, then drag your existing iPhoto app (not the library, just the app) to the trash

Install the App from the App Store.

Sometimes iPhoto is not visible on the Purchases List. it may be hidden. See this article for details on how to unhide it.

http://support.apple.com/kb/HT4928

One question often asked: Will I lose my Photos if I reinstall?

iPhoto the application and the iPhoto Library are two different parts of the iPhoto programme. So, reinstalling the app should not affect the Library. BUT you should always have a back up before doing this kind of work. Always.

Hi. Any progress on this? People have answered jmay0520's question wrongly, referring to iPhotos (he is not talking about iPhotos, but the Yosemite Photos app). I have imported my Aperture library into Photos and many thumbnails are messed up, many show a preview of picture from other albums. Anyone knows how I can rebuild thumbnails in Photos (not iPhotos). It's a 10,000 pictures library with many folders and albums. Original pictures stored on iCloud.

jmay0520 wrote:

(BTW, shockingly bad documentation on Photos. In fact, you can't find help on support.apple.com for Photos, only reference is for iPhoto). Thanks!

Try https://www.apple.com/support/mac-apps/photos/

You can get to it from the main support page by clicking or swiping to get to the second page showing the Mac Apps icon, clicking on that, & selecting Photos on the list in the resulting page.

Try How to Rebuild Thumbnails in a Photos Library from the Photos User Tips page.

To regenerate the thumbnails in photos give the following a try:

Select all of the photos, Control (right) - click and select Rotate clockwise from the contextual menu.

With the photos still selected, Option-Control (right) - click and select Rotate counterclockwise.

This will force Photos to regenerate the thumbnails.

Thanks to léoine for this tip.

I had the same fuzzy thumbnails problem. Rebuilding them as described in this link solved the problem.