During image upload, I get the following warning :
Warning: trim() expects parameter 1 to be string, array given in /wp-admin/includes/image.php on line 300
The line 300 is:
$meta['iso'] = utf8_encode( trim( $exif['ISOSpeedRatings'] ) );
The error is that $exif['ISOSpeedRatings'] can be an array, for example Array ( [0] => 200 [1] => 200 ). So the trim() function returns the warning.