I tested again using a different invocation of Easy File Uploader on our site, to upload photos. This is the error message I received:
ERROR: The uploaded file type is not permitted.
MIME detected by PHP: (image/png; charset=binary)
MIME detected by Browser: image/png
I’m a bit dubious about the “charset=binary”, as images don’t have character sets, right?
One additional thing that has changed (besides the Joomla version update) is a newer version of PHP. Should the PHP MIME type detection function be returning the “charset=binary” notation?