Correctly handle 0x0 sizes returned from getimagesize, using shim f…

…allback for AVIFs

src/wp-includes/media.php

@@ -5512,7 +5512,11 @@ function wp_getimagesize( $filename, array &$image_info = null ) {
 		}
 	}
 
-	if ( false !== $info ) {
+	if (
+		false !== $info &&
+		// Some PHP versions return 0x0 sizes from `getimagesize` for unrecognized image formats, including AVIFs
+		! ( empty( $info[0] ) && empty( $info[1] ) )
+		) {
 		return $info;
 	}