Updated for 7.0
Within the left side bar under NEWS & CALENDAR, select Gallery (not the Gallery option at the top of the page). This will take you here:
Select the gallery in which you wish to add pictures to. This will take you here:
Within the box titled Add New Photos, select the empty box underneath the text ‘Max File Size’. A pop up will appear that looks like this:
Select the picture that you wish to add. Then, select Open. A new thumbnail of the picture will be displayed within the box titled Photos. It will look like this:
