Upload a base64 string as image to the WordPress media library

wordpress-upload-base64.php

<?php
/**
 * Save the image on the server.
 */
function save_image( $base64_img, $title ) {

	// Upload dir.
	$upload_dir  = wp_upload_dir();
	$upload_path = str_replace( '/', DIRECTORY_SEPARATOR, $upload_dir['path'] ) . DIRECTORY_SEPARATOR;

	$img             = str_replace( 'data:image/jpeg;base64,', '', $base64_img );
	$img             = str_replace( ' ', '+', $img );
	$decoded         = base64_decode( $img );
	$filename        = $title . '.jpeg';
	$file_type       = 'image/jpeg';
	$hashed_filename = md5( $filename . microtime() ) . '_' . $filename;

	// Save the image in the uploads directory.
	$upload_file = file_put_contents( $upload_path . $hashed_filename, $decoded );

	$attachment = array(
		'post_mime_type' => $file_type,
		'post_title'     => preg_replace( '/\.[^.]+$/', '', basename( $hashed_filename ) ),
		'post_content'   => '',
		'post_status'    => 'inherit',
		'guid'           => $upload_dir['url'] . '/' . basename( $hashed_filename )
	);

	$attach_id = wp_insert_attachment( $attachment, $upload_dir['path'] . '/' . $hashed_filename );
}