In jQuery how to add ID to img tag

[ravi142]

Hello
How can i add ID='xyz'in IMG tag

<div class="main-banner">
<img width="1000" height="242" alt="cropped-Penguins.png" class="attachment-full" src="http://../cropped-Penguins.png">
</div>

JQuery which i have tried

jQuery('.main-banner').append("img").attr('id','xyz');

But Not Work.
Give me suggestion
Thank you

[noelthefish]

$("img").attr("id","xyz");