Actually these files that don't work are just a bit larger... I've set the max file size to 5,000,000 bytes but I guess that's not working because its really around 2MB.
Ok error_reporting is on and there's no errors. FILES array = Array ( [image_file] => Array ( [name] => Reservoir 08 013.JPG [type] => [tmp_name] => [error] => 1 [size] => 0 ) )