This resolves a few WPCS warnings:
{{{
Variable "$sX" is not in valid snake_case format, try "$s_x"
Variable "$sY" is not in valid snake_case format, try "$s_y"
}}}
The `$sX` and `$sY` variables are renamed to `$original_width` and `$original_height`, respectively.
Additionally, the `$fwidth` and `$fheight` variables are renamed to `$full_width` and `$full_height`, for clarity.
Follow-up to [11965], [22094], [56400].
See #58831.
Built from https://develop.svn.wordpress.org/trunk@56411
git-svn-id: http://core.svn.wordpress.org/trunk@55923 1a063a9b-81f0-0310-95a4-ce76da25c4cd
