. . . . Is there a way to keep those notes but not have them on the picture itself . . . .
There are 2 ways of doing this:
If the information is for reference only then adding the information to the image properties information, using Windows File Explorer - right clicking the image to open its Properties as shown below and on the details tab add the appropriate data in the available options.
If you need the information accessible in Photostory, eg for while adding narration, then the text can be hidden by dragging down the transparency handle indicated below when not required.
You can also keep some information in the project by right-clicking an image and selecting properties. You can rename the Object and add a comment. This does not affect the original file, only the object in Photostory, and the information is only in that project.