That's a great question and very thoughtful. In your ideabook, go to the top and select edit. Go to any picture where you have entered a comment and click the box below the comment that says "Make comment private". Do this for each picture. When you have finished, go back to the top of that page and click on Done.

In the future when you save a picture, there is always a box below the comment box where you can check it to make it private.

Private comments can only be seen by you.

Thanks Deborah