Answered: I want whole image or div clickable and it should redirect to question page.

Try

$q_list'qs']$index]'content'] = '<a href="/'.$postinfo$question'raw']'postid']].'" rel="nofollow">'.$image.'</a>';

Or maybe just

$q_list'qs']$index]'content'] = '<a href="/'.$question'raw']'postid'].'" rel="nofollow">'.$image.'</a>';

Correct syntax errors if any.

It is advisable to use rel="nofollow" tags because the links will redirect to the questions will full urls, and it won't hurt your website crawl budget if Googlebots discover them.