Once you've entered the Gallery from the Campaign Editor, you can add photos to share with your supporters.
To add photos, click Edit on the Add New Photos section.
Click the Select File button, navigate and pick the file from the file viewer that pops up. Once you hit Select or Open on the File Viewer popup, you'll see an uploading file overlay, and the image will be added. You can then Edit or Remove the added image from the next section, called Edit Photos.
Please note that the maximum image size is 10MB.