Make sure first that you have the latest Noteshelf version by going to the iTunes Store and downloading the latest version.
There are actually two ways to modify your photos, one process is via the Flatten mode.
After adding the photo on the page, just long press on it then tap on "Flatten."
Tap on the scissor icon (Cut-Paste) on the toolbar then select the whole image and from there, you will be able to resize, rotate and even move the photo.
Another way to modify your photos is to tap on the photo then select "Edit."
Resize the photo by adjusting the photo scale.
Tap on "Done" if you're satisfied with the photo size.
If you want to rotate the photo, tap on Edit again then just hold and pinch the photo on the page and rotate it any way you want. You can both resize and rotate the photo while on Editing mode.
Check the size and placement of your photo.
If you're satisfied with how it looks like on the page, hit on "Flatten"
Tapping on "Flatten" will merge the photo on the page, enabling you to erase it, like a handwritten note.