Yes, to copy photos between projects:

1. Click Projects on the main menu at the top of any page.
   
   
2. Select the folder containing the project you want to add photos to.
   
   
3. Choose the project you want to add photos to.
   
   
4. Click on the Edit button near the right side of the page.
   
   
5. Click Photos on the progress bar.
   
   
   
   
6. Click the Add Photos button near the right side of the page:
   
   
   
   
7. Choose the Project Photos icon:
   
   
   
   
8. Click on the Show menu, then select the name of the folder containing the project you want to copy images from:
   
   
   
   
9. Select the image(s) that you want to add to the current project.  When selecting multiple images, they are added to the project in the order you select them. Click the Add Selected button when you are done: