post_per_page in wordpress not rendering properly on the page - php

Question

Hi i have this wordpress site and the pages will display images on it. Now my problem is when i add post_per_page => '50' then when i refresh the page the number of posts per page is not rendering correctly. Here is my code below.
<?php
query_posts( array(
'post_per_page' => 50,
'cat'=> '7',
'order' => 'ASC'
) );
?>
<?php while(have_posts()) : the_post(); ?>
<div class="single-gallery anim-5-all interoors masonryImage mix span-4">
<div class="img-holder">
<?php
$thumb = wp_get_attachment_image_src( get_post_thumbnail_id($post->ID), 'medium' );
$url = $thumb['0'];
?>
<img src="<?=$url; ?>" alt="">
</div>
</div><!-- /.single-gallery -->
<?php endwhile; wp_reset_query(); ?>
Now it will display 9 images on the page. Can someone help me figured this thing out? Any help is muchly appreciated. TIA

Answer 1

For a first, I fond mistake in your query arguments
'post_per_page' => 50,
There is no such argument for wp_query loop use instead it
'posts_per_page' => 50,
For a second there is quote from a wodpress codex about query_posts function
Note: This function will completely override the main query and isn’t
intended for use by plugins or themes. Its overly-simplistic approach
to modifying the main query can be problematic and should be avoided
wherever possible. In most cases, there are better, more performant
options for modifying the main query such as via the ‘pre_get_posts’
action within WP_Query.
I can recomend you to use standard wordpress loop
<?php
$args = [
'posts_per_page' => 50,
'cat' => '7',
'order' => 'ASC',
];
// The Query
$query = new WP_Query( $args );
// The Loop
while ( $query->have_posts() ) : $query->the_post(); ?>
<div class="single-gallery anim-5-all interoors masonryImage mix span-4">
<div class="img-holder">
<?php
$thumb = wp_get_attachment_image_src( get_post_thumbnail_id($post->ID), 'medium' );
$url = $thumb['0'];
?>
<img src="<?=$url; ?>" alt="">
</div>
</div><!-- /.single-gallery -->
<?php
endwhile;
wp_reset_postdata();
?>