Tip of the day: MIME types for Paperclip & IE8

If your users are receiving this kind of  error in your Paperclip-enhanced models

And your uber Cucumber regresssion tests aren't picking it up, despite having the following standards-based MIME type validations;
then you might check to see what browser they're using.
Are they using Internet Explorer? Internet Explorer 8 perhaps?
Well you might want to add something along the lines of image/pjpeg to your validations. 
Google killed off IE6. Lets hope they do the same for IE6+2 soon.