Before this commit, the No Change status wasn't properly set because the `filehash` wasn't passed to `_binary_set_headers` and because the status was not changed to 304 if it was already set to 200 earlier. This commit fixes this issue and also prevents images to be processed in `content_image` if the status is 304. opw-2008426 closes odoo/odoo#34032 Signed-off-by: Christophe Simonis <chs@odoo.com>