Photo Stream Woes

[IslandAndy]

I have a brand new Mac Mini, all set up and configured and am now having trouble with adding photos to Photo Stream. I'll preface this with I am new to the Mac world. I have an iPhone 4S and the iPad Retina. My Mac Mini will display the photos from both devices in the photo stream menu. However yesterday I imported photos into the iPhoto on the Mini from my digital camera. No problems. But as I drag them, or use the Add To function to put them into the Photo Stream, they don't move. none. This happened last time I tried and finally 2 of 20 moved to the stream. What am I doing wrong??