First, please stop posting over and over. We are actual people and it can take a while for someone to get to you.
Second, I am going to assume you mean your home screen (as in your wallpaper), since a phone doesn't have a homepage.
If is the wallpaper you are referring to then you just need to tap and hold the background of the screen. Not on an icon. Then tap the option for wallpapers and choose what you want. You can also just go into your gallery, tap and open the image you want to use and set it as the wallpaper from there.
Now if you are referring to an image in a specific app, then you need to explain what app you are referring to.