i’m running into the same problem, i have been able to track this down into the core code at:
wp-includes/media.php-> image_downsize function which is returning false for all intermediate_sizes. This function is called by wp-admin/includes/media.php->image_size_input_fields function which checks if the indermediate size is set to true. ( $enabled = ( $downsize[3] || 'full' == $size ); )
after which the following line executes:
$html = "<div class='image-size-item'><input type='radio' ".( $enabled ? '' : "disabled='disabled'")."name='attachments[$post->ID][image-size]' id='{$css_id}' value='{$size}'".( $checked == $size ? " checked='checked'" : '') ." />
since intermediate size is false, which is the third element in the array, enabled is set to false, which caused disabled to be echoed. i wondering if this is a wordpress bug with release 2.7.1 or caused by a plugin?
