cover image in ask question page

Just add this code to your css file:

.page-header.questions-header {
    background-image: url("/wp-content/themes/askbug/images/code.jpg");
    background-position: center center;
    background-repeat: no-repeat;
    background-size: cover;
}

And just replace

/wp-content/themes/askbug/images/code.jpg

With your image url.

Copy askbug/template/anspress.php to your child theme.

And paste this code at the top of file:

<?php if(!is_question()): ?>
	<div class="page-header questions-header clearfix">
		<div class="container">
			<h1 class="entry-title">Questions - AnsPress Support</h1>
			<?php dynamic_sidebar( 'question-search' ); //Replace with your own registered position name ?>
		</div>
	</div>
<?php endif; ?>

And simply add background for class .questions-header