Problem: ImageMagick warnings show up when uploading digital objects

[anvit]

Current Behavior

Steps to reproduce the behavior

1. Attempt to upload a digital object.
2. Look at AtoM's log's and notice there are warnings about the convert command being changed.

Expected Behavior

No warnings should be present when uploading digital objects

Possible Solution

This is likely due to a newer syntax for convert commands in imagemagick. plugins/sfThumbnailPlugin/lib/sfImageMagickAdapter.class.php will have to be updated to follow the updated syntax.