How to zoom out imageOverlay on leaflet.js?

I want to show the my image layer on map but the image is over zooming. Can anyone help me to zoom out this layer, i want to zoom out approximately to 82%. This is my code:

    L.imageOverlay('myPicture.png', L.latLngBounds(L.latLng(-5, 103.593810), L.latLng(1.355568, 103.703674)), {
        opacity: 1,
        zindex: 100,
    }).addTo(layerpicture);

Thank you guys.