How to change the logo of a child page on Wordpress - wordpress

Question

Header.php
<div class="site-branding">
<div class="container">
<?php
***if ( is_page('/category/fitness/') ) ?>{
<img src="<?php bloginfo('template_url'); ?> /assets/images/fitnesslogo.jpg"
width="100" height="100"/>
}***
<?php
if ( function_exists( 'the_custom_logo' ) ) {
the_custom_logo();
}
if ( is_front_page() && is_home() ) : ?>
<h1 class="site-title"><a href="<?php echo esc_url(
home_url( '/' ) ); ?>" rel="home"><?php bloginfo( 'name' ); ?></a></h1>
<?php else : ?>
<p class="site-title"><a href="<?php echo esc_url( home_url(
'/' ) ); ?>" rel="home"><?php bloginfo( 'name' ); ?></a></p>
<?php
endif;
$description = get_bloginfo( 'description', 'display' );
if ( $description || is_customize_preview() ) : ?>
<p class="site-description"><?php echo $description; /*
WPCS: xss ok. */ ?></p>
<?php
endif; ?>
<?php do_action('boston_after_site_description'); ?>
</div>
</div><!-- .site-branding -->
The page slug is /category/fitness as the URL on the end of the page suggests when I go to the page it looks like it's not interpreting the img src, but is displaying '{}' tags that are around the img scr instead

Answer 1

You have:
***if ( is_page('/category/fitness/') ) ?>{
<img src="<?php bloginfo('template_url'); ?> /assets/images/fitnesslogo.jpg"
width="100" height="100"/>
}***
But it should be
if ( is_page('/category/fitness/') ) {
echo '<img src="'.bloginfo('template_url').'/assets/images/fitnesslogo.jpg" width="100" height="100"/>';
}

Answer 2

I'm not familiar with the Boston theme, but it looks like it's checking to see if a custom logo has been added and if so to use it. So, I would think the following would give you what you're looking for.
<?php if ( is_page('/category/fitness/') ) : ?>
<img src="<?php bloginfo('template_url'); ?>/assets/images/fitnesslogo.jpg" width="100" height="100"/>
<?php else : ?>
if ( function_exists( 'the_custom_logo' ) ) {
the_custom_logo();
}