image numbers in iphoto

You are talking about the title - iPhoto set the title to the file name on import Photos does not - you enable viewing the title in the View menu ==> metadata and check Title plus any other desired Metadata you want to view - you can set the title to the file name using one of these user scripts - : Script: Batch Changing the Titles to the Filename w/Extension or Script: Changing the Title to the Filename without Extension - and if you prefer Old Toad has complied these scripts into applications available from his web site - http://www.oldtoadstutorials.net/No.P01.html

LN

On my previous mac mini, Iphoto displayed the image number below each photo.

iPhoto is still showing the filenames with the image numbers below the thumbnails.

Are you now using Photos for Mac instead of iPhoto?

Photos will not use the filenames as the default title. You have to copy the filenames to the title field, if you want to see them in the browser below the thumbnails. You could run an Apple Script to copy the filenames for several selected photos at once to the title.

See: : Script: Batch Changing the Titles to the Filename w/Extension

Then enable to show the titles in the View Menu: View > Metadata > Titles.

To minimize the motion consider to change the System Preferences > Accessibility > Display: enable "Minimize Motion".