Android : How To Reuse Existing Fragment instead of recreating it (after rotation)

I am using an Activity with 2 fragments: 1 Fragment - side menu 2nd Fragment - main window.

For one of my fragments that appears in the main window, it shows an image in a relative layout.

When I rotate the device, the fragment is re-created and now I have 2 of the same images shown on the device since Android re-creates and adds the fragment instead of reusing it.

I have tried doing a trick in my activity:

if (savedInstanceState==null) {
//load and replace to initial fragment
}

however I cannot seem to 'load' or 'save' the existing fragment in my main window correctly.

Can anyone help me with this? I have tried a few solutions on SO but nothing has worked so far.

Thanks