You can make your own templates. I used Photoshop to create a blank document, about 1095x800 (pixels) and saved as a photo. You could also take a photo or screen shot of an image.
Once you have the image, save it to your Gallery (or Dropbox, if you are using).
Next, open a new note in S-Note. In the upper left corner, click the pencil/paper icon to switch into Edit mode. Then, in the upper right corner, click the 3 arrows (options) and choose Change Background. Instead of using one of the stock images, click the Gallery button in the upper right corner and browse to the image you saved in your gallery (you will have other options as well, depending on what apps are installed on your device). Navigate to and choose your template, then crop to size. If you set your original image at about 1095x800 you should be able to resize to the maximum. Close to exit back to SNote and now your image will be in the background of the note.