How can I hide sensitive photos
There are many ways to achieve this.


Exclude such folders in the Spotlight search. Any one else using the Mac can easily find and go through the content.
Create a new Disk Image (preferably encrypt it) in Disk Utility and it is a separate disk which grows and shrinks based on the contents. You could also use apps like Knox to achieve the same.
Try apps like Skedaddle to hide from Finder. Skedaddle protects the files with a password and Spotlight cannot find it. It does not encrypt the data.