refactor cropped images into explore/posts/intro

app/logical/image_cropper.rb

@@ -0,0 +1,12 @@
+class ImageCropper
+  def self.enabled?
+    Danbooru.config.aws_sqs_cropper_url.present?
+  end
+
+  def self.notify(post)
+    if post.is_image?
+      sqs = SqsService.new(Danbooru.config.aws_sqs_cropper_url)
+      sqs.send_message("#{post.id},https://#{Danbooru.config.hostname}/data/#{post.md5}.#{post.file_ext}")
+    end
+  end
+end