Kathleen, I'm not good at explaining things, but I'll try.
Copy the link at the top of the page of the art you want to share.
In your G+ status update section, where it has Text, Photos, Link, Video, Event, Poll....click on "Link."
Then, when it shows "attach:", paste your link there. You can still add text in the white section over top of that, such as "new upload" or whatever you want.
When you paste the link, the image will come up. You can leave it as is or hover over it. A thin black bar will come up with < and > where you can click on these and change the way the image shows. I usually just leave it as it comes up.
Not sure if this is what you need. If not, PM me and I'll try to help you more!!