image_decorator.rb

Spree::Image.class_eval do

 #   before_post_process :rename_attachment

	attachment_definitions[:attachment][:convert_options] = { 
        'all' => "-strip -trim -gravity center -filter Catrom",
		'mini' => "-strip -trim -gravity center -filter Catrom",
		'small' => "-strip -trim -gravity center -filter Catrom", 
		'product' => "-strip -trim -gravity center -filter Catrom",
		'large' => "-strip -trim -gravity center -filter Catrom"
	} 
end