Q: Lost all my iphoto photos!!

I have lost all my iphoto photos - all 26,000 of them!!!

I was cleaning up my computer yesterday - putting old files in trash.

Then when I went to open up my computer I got a different desktop picture - space one - not my screensaver that I had set up

I shut down & reopened my computer - and it can back - iphotos, and correct desktop screensaver

This morning it has all gone again and I have the generic screen saver

I do have a time machine - but it hasnt' been on for 12 months (long story)

Can anyone help???