Convert image data to binary text for vcard

I need to include an image in a vcard file. The image is supposed to be in binary format. I create the image data as follows:

NSData *imageData = UIImageJPEGRepresentation([UIImage imageNamed:@"Pic1"], 1.0);

I have unsuccessfully tried encoding using the following 2 methods:

vcardString = [vcardString stringByAppendingFormat:@"PHOTO;ENCODING=b;TYPE=JPEG:%@\n", [imageData base64EncodedString]];

AND

vcardString = [vcardString stringByAppendingFormat:@"PHOTO;ENCODING=b;TYPE=JPEG:%@\n", [imageData description]];

Any advice on how to get the image data properly encoded to binary would be appreciated. Thanks