in case that might be helpful to anyone.
I was having the same issue – the image would return value “1” even though I had set to return the URL.
I had the value saved to a variable like this:
$image_overview = get_field(‘overview_img’);
Well, so using the variable I was getting the “1” value, but using directly the get_field function returned the URL as it should.
Can’t explain why this happens though…