iphoto only sharing photos to icloud one at a time

Hi, so this is gonna seem like kind of a random problem, I wast just wondering if anyone else has experienced this and if they know a solution.

I don't use iPhoto a lot so I'm a little inexperienced with it. But I created a new album today on iPhoto and I tried to share the photos in the album to iCloud so I could view them in my photo stream. But what I'm finding is that even if I select all the photos in the album, when I try to share them to my photostream, it only shares the first one. So one photo from the album appears in my photostream but none of the others that I had selected.

This effectively means that if I want to share all the photos in this album to my photostream, I'll have to do each one manually.

Obviously this would be mega tedious and time consuming. I just don't understand why, even though I've got multiple photos selected it's only sharing one at a time!

If it's helpful to know, my OS X version is Yosemite 10.10.2 and I'm using iPhoto version 9.6

Cheers,

Al