Thanks for the reply Zentalquabula but what I want to do is change the "Creation Date" properties when you edit an image. I want to put in say Aug 1976 as some of my photos are really old.
Thanks

After an aweful lot of clicking and trials, I managed to get this to work.
Thanks for your link and help guys.

Hi, I just wanted to modify the Creation Date of my old photos in my Gallery. Some of the photos go back to 1976. I just had to click back on the little Calendar in Edit Photo Properties to get to the right date, then hit "Done". Sometimes this doesn't work and I have to start again. I have to do > 800 photos with 360 mouse clicks on each one (that's a lot of clicks). There must be an easier way!

I have pictures from 1869 and I was able to input the creation date.
I type the date in a text file, then I copy the date to the clipboard, then I double click the year in the calendar and I paste the date from the clipboard. It works for me.
WHAT? Pictures from 1869? Well yes, those are wet-plate collodions from 1869 with some of my ancestors which I did scan.
I put all my ancestors in piwigo.