[2.6]->[2.6.1] = Press this: no pictures and send fails

Hello, “press this” stopped working properly for me since 2.6.1, the pictures in the “Photos” tab are all blank and trying to submit the article, sends only the title, leaving the article empty and returns this error:

Catchable fatal error: Object of class WP_Error could not be converted to string in /home/{user edited}/public_html/wp-admin/includes/file.php on line 260