Encrypting an image file and storing in SQL Server 2005

I was wondering what the best way would be to encrypt a .jpg file and decrypt it back to an image?  Currently, I am reading the image file and storing it in an Image datatype field.  I am using SQL 2005.

 I was looking at asymetric encryption/decryption but wasn't sure if that was the path to go or if there was another way.  The image file is a signature so that is why I was wondering about the encryption.  Without out, someone could get the raw data and convert it back to an image correct?

 Thanks,
Greg
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