If you have enabled Show Categories on your phone, you can set directories in Galaxy S3 File Manager to have quick access to image, video, music, document. Follow the instructions:
1. Open "My Files" App
2. Press "Menu Button" and go to "Settings"
3. Mark "Show Categories" to enable this feature. If you want to hide categories and disable Show Categories, you need to unmark it
4. Now, select new directories for each of your multimedia contents. (for example, tap "Set Image Directory" and then choose a folder and the new directory for images)
5. From now on, when you open the Default file manager of your Samsung Galaxy device, tapping each Directory takes you to the folder you already defined.