WordPress/wp-includes
Joe McGill 75df12f322 Media: Improve image filetype checking.
This adds a new function `wp_get_image_mime()` which is used by
`wp_check_filetype_and_ext()` to validate image files using
`exif_imagetype()` if available instead of `getimagesize()`.

`getimagesize()` is less performant than `exif_imagetype()` and is
dependent on GD. If `exif_imagetype()` is not available, it falls back to
`getimagesize()` as before.

If `wp_check_filetype_and_ext()` can't validate the filetype, we now return
`false` for ext/MIME values.

Merges [39831] to the 4.7 branch.

Built from https://develop.svn.wordpress.org/branches/4.7@39832


git-svn-id: http://core.svn.wordpress.org/branches/4.7@39770 1a063a9b-81f0-0310-95a4-ce76da25c4cd
2017-01-11 13:12:34 +00:00
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2017-01-11 05:21:59 +00:00