If you try to upload a file that contains HTML in the EXIF data using Special:Upload it gives you the following error:
"This file contains HTML or script code that may be erroneously interpreted by a web browser."
If you try to upload the same file using UploadWizard, it gives you the following error:
"This file might be corrupt, or have the wrong extension."
It would be nice if the UploadWizard error were more specific.