Details:
- From the Pages module, "Add page" area, give the new page a name;
- Choose "Image Gallery" for the Page Type;
- Select a Parent Page and visiblility if applicable;
- Click "Add"
To add a single picture
- Click the "Add Image" button
- Enter a Title,
- Add (optional but recommended) alt text
- Add an (optional) description
- Browse to find the picture
- Click "Save"