Rats! You probably also tried the option and command (apple) keys as modifiers while re-sizing. The only other suggestion I have is to reduce the object BEFORE pasting it into your note.
To do this in Preview, first make a copy of your object with a different name and then work on the copy. Open the object (picture) in Preview and under the Tools menu, select Adjust Size… . Make sure the Scale proportionally box is checked ;) as well as the Resample image box. Reduce the width or height numbers by a guesstimate amount to reduce the size of the graphic and click OK. Copy the now-smaller graphic into your note.
Excuse me if this is all too basic; no offense intended.