What is the best way to solve the image size problem in WordPress?

Question

CMS

Good day. The task was to display WordPress blog posts with preview images. But the ambush is that the last 5 entries should have different thumbnail sizes. There is an idea to make the output of images in the largest size (last entry), and then assign classes to the remaining 5 blocks using js and reduce the size to the required parameters using css. I'm attaching a screenshot for better clarity. The project is made up on Bootstrap, the layout is adaptive.
Are there other approaches to solve this problem?

Answer 1

<?php $loop = 0; ?>
<?php if(have_posts()) : while(have_posts()) : the_post();?>
<?php $loop++; ?>
<?php if( $loop == 1) {
//Do action for large image
} elseif( $loop == 2 ) {
//Do action for big image
} elseif( $loop > 2 && $loop <= 5 ){
//Do action for middle image
} elseif( $loop > 5 ) {
//Do action for small image
}?>
<?php endwhile; endif;?>

This is the easiest way to implement according to your example

Answer 2

Well, what is the actual problem? I counted 4 different types of pictures.
add_image_size