android tasks for picture to show up in gallery

My app is running through json and database of my website. Its a free ad or classified posting website app. At the moment my app is having issues with image preview when clicked on a thumbnail in any ad on android phone. To avoid any other complications i just want to know is it possible for us to show the image preview in gallery of phone like you view other pictures you have in your mobile? You have to do this if you know.