Get post author image - Wordpress - php

Question

In WordPress I need to fetch the Author image of author who created post. I tried to get the profile image in this way, but it didn't work.
Here is the code I have written to get other author_meta_details.
<div class="row">
<div class="avatar col-md-3">
<picture class="avatar-circle">
<?php if($avatar = get_avatar(get_the_author_meta('ID')) !== FALSE): ?>
<img src="<?php echo $avatar; ?>" alt="">
<?php else: ?>
<img src="/wp-content/themes/lymited-child/images/avatar-image.png">
<?php endif; ?>
</picture>
</div>
<div class="author-details col-md-9">
<div class="author-name"><strong><?php echo get_the_author_meta('first_name'); ?></strong> - <?php echo get_the_author_meta('nickname'); ?>
</div>
<div class="author-summery"><?php echo get_the_author_meta('description'); ?>
</div>
</div>
</div>

Answer 1

Try this
<?php
$get_author_id = get_the_author_meta('ID');
$get_author_gravatar = get_avatar_url($get_author_id, array('size' => 450));
if(has_post_thumbnail()){
the_post_thumbnail();
} else {
echo '<img src="'.$get_author_gravatar.'" alt="'.get_the_title().'" />';
}
?>
OR Remove this if the condition and try
echo get_avatar( get_the_author_meta('ID') );

Answer 2

get_avatar() returns <img> element so you don't need to wrap it to img again
Also you need to wrap $avatar = ... to parenthesis as = priority is lower than !==
try to replace this
<?php if ( $avatar = get_avatar(get_the_author_meta('ID')) !== FALSE): ?>
<img src="<?php echo $avatar; ?>" alt="">
with this
<?php if ( ( $avatar = get_avatar(get_the_author_meta('ID')) ) !== FALSE): ?>
<?php echo $avatar; ?>