I had to do this...
From my Chrome inbox I click on apps (the nine little squares at the top rt.) and get photos then upload (top rt)
it will go to your hard drive and let you pick the photos to up load
When it is finished there will be "add to Album" and "new shared album"
A new box comes up and at the top is "new shared album". Click on this. After the first time you will click on "add to album"
The new album will show up ready for you to name it and then click the SHARE box at the top.
On the bottom of the new box that comes up, click on Google+
You should now have this album in Google+
Open the album in Google+ and go to each photo you want to post one photo at a time and rt click on it and select "open image in new tab
A new tab will appear at the top of your page for each image you do this with.
When all of your image tabs are lined up across the page, go to your MLS page. Now open the new tab with the photo in it, rt click and select "copy image address"
Click on the camera icon in MLS and in the box that opens, rt click and paste