Explicitly checking for false to safeguard a match at position 0 of $…

…content, which would satisfy the if-statement's condition. (#38505)

packages/block-library/src/image/index.php

@@ -20,7 +20,7 @@ function render_block_core_image( $attributes, $content ) {
 		// which now wraps Image Blocks within innerBlocks.
 		// The data-id attribute is added in a core/gallery `render_block_data` hook.
 		$data_id_attribute = 'data-id="' . esc_attr( $attributes['data-id'] ) . '"';
-		if ( ! strpos( $content, $data_id_attribute ) ) {
+		if ( false === strpos( $content, $data_id_attribute ) ) {
 			$content = str_replace( '<img', '<img ' . $data_id_attribute . ' ', $content );
 		}
 	}