+ * img: stop ImageMagick trying to be clever if filenames contain a colon,
+ avoiding mis-processing
+ * HTML-escape error messages, in one case avoiding potential cross-site
+ scripting (OVE-20160505-0012)
+ * Mitigate ImageMagick vulnerabilities such as CVE-2016-3714:
+ - img: force common Web formats to be interpreted according to extension,
+ so that "allowed_attachments: '*.jpg'" does what one might expect
+ - img: restrict to JPEG, PNG and GIF images by default, again mitigating
+ CVE-2016-3714 and similar vulnerabilities
+ - img: check that the magic number matches what we would expect from
+ the extension before giving common formats to ImageMagick