Updates to filter 'acf/get_post_id' - validate post_id type to int

Signed-off-by: Elliot Condon <e@elliotcondon.com>
Allow post_id to be numeric or string type

Signed-off-by: Elliot Condon <e@elliotcondon.com>
Updates to image JS

Signed-off-by: Elliot Condon <e@elliotcondon.com>