@yoderman94,

Do you want to remove all or just some? To dequeue files, the dequeue function needs to run after image store has queued the styles.

If you want to remove all css, just go to settings > general and uncheck “Use CSS”

To dequeue some try:

function dequeue_image_store_styles(){
wp_dequeue_style('imstore');
wp_dequeue_style('ims-single');
wp_dequeue_style('imstore-store');
}
add_action( 'wp_enqueue_scripts', 'dequeue_image_store_styles', 100 );