In my mail template I used image path as below :
<img src="{{ URL::to('/images/logo.png') }}" alt="logo" download="false" style="width:50%">
It is working with normal mail (without the queue) but not in mail in queue.
By inspecting element in mail i found that when for normal mail image path is as below :
https://app.site_domain.com/images/logo.png //as expected
But for mail queue it is :
http://localhost/images/logo.png