My menu elements supposed to be on top of the image. Like this

<div class="menu">...</div>
<img src="..."/>
However when I add opacity to the style of the image, the menu elements lay under the image

<div class="menu">...</div>
<img src="..." style="opacity:0.9"/>
Does anyone know what’s going on and how do I fix this issue?
My bet would be the opacity is giving a z-index to the image. Have you tried adjusting the z-index on the menu?