Hi, Daria. Do you mean you want to hide a photo folder in samsung gallery app? If so, please keep reading.
Do you know .nomedia file? It is a BLANK file with “.nomedia” as the file name. You can create this file in a folder so as to inform the media scanner that don't show any media files inside this folder. So that you can use this trick in apps such as Gallery.
You can do this simply by:
1. Install and launch the ES File Explorer app on your samsung.
2. Open the ES File Explorer and browse the folder that you would like to hide the photos inside it.
3. Next, tap the menu button and then select New.
4. Select File and then enter filename .nomedia
With the steps above, you can create the .nomedia file and your folder with this file will hide from the Gallery.