[magick-users] Problems handling certain jpgs.

[omicronpersei8 at imagemagick.org]

> convert: 450: unable to copy profile `invalid profile length'

This message is thrown when reading a reading a PNG image with a zero-length
profile.  Your original images are JPEG so you must be converting them to
PNG somewhere because it does not appear possible the message could be
generated from the JPEG reader.