No, you don't have to max the amount of photos/videos for collecting cash.
http://hotcandyland.com/hotline/5199/everytime-upload-pics-movies-booble-only-subscribes-cash-that
Like the others mentioned in your former post, you have to set a reasonable fee for your website. In this case reasonable means you should get a client growth and keep some money. Then you have to wait and you can collect money via cash symbol over the booble building.