iphoto : First time Slideshow sharing

iPhoto 9.6.1 (910.42)

OS X Yosemite

iMac 2.8 Ghz Intel Core 2 Duo

I have this 280 pic iPhoto Slideshow I want to share with PC-using friends.

I clicked the 'Share' arrow, chose a middling quality, and I believe it said it would go to iTunes ?

Then walked away as I knew uploading would take a long time.

Hours later uploading had stopped - completed ? - and I expected to be asked to 'Save' with a file name. But nothing.

How can I check what's happened ?

It can hardly be successful as I have no web address to tell others ?

But all that uploading must have gone somewhere ?

Nigel