First of all, unlock your Android and go to the main menu. Search for the stock file manager app. If you don’t have the application, don’t worry as you can get it from Android Market. Just sign in to Android Market from your Google account and search for File Expert, Astro File Manager, or OI File Manager. It is to be noted that you can download any of the three applications.
Keep in mind that you can also go to your Android’s file manger or SD card from your personal computer which makes the process faster and easier.
After you have downloaded the file manager application, open it and add a new folder which starts with (.) and followed by the name, for example, .mypics.
Now, move your pictures (which you want to hide from others) into the folder which you have just created. You will notice that the pictures which you have sent to that folder will no longer be visible in your default Gallery app of your Android or any other picture viewer which you may have and will only be shown in the file manger.