In Imagestream click on Select All at the bottom of the student list on the left.
Then click on Add to move students over to the right, click on Export Wizard
On this screen you select Administrative software and hit Next.
This screen you click on the administrative software drop down menu and select one of the Lifetouch formats to use. For example if you want firstnamelastname (John Doe) etc.
Then you click on Browse and select the folder you created on your desktop, in this folder we will export the images. Then click Finish.
You are done. You should see images like this: