Paperclip svg图片上传停滞不前

Question

我有一种关系，用户可以有很多设计。

用户模型：

class User < ActiveRecord::Base  le
has_many :designs
accepts_nested_attributes_for :designs

设计模型：

class Design < ActiveRecord::Base
has_attached_file :design, 
:styles => { :medium => "300x300>", :thumb => "100x100>" }, 
:default_url => "/images/:style/missing.png" , 
 :storage => :dropbox,
:dropbox_credentials => Rails.root.join("config/dropbox.yml"),
:dropbox_options => {environment: ENV["RACK_ENV"]}
belongs_to :user
end

设计控制器。

def create        
if current_user.designs.create(design_params)
  flash[:alert] = "Successfully created the design."
  redirect_to designer_show_path  
else 
  render designer_create_path
end
end

def new
   @design = current_user.designs.build
end

现在一切正常，除非我上传图片后，它似乎永远继续下去甚至不到10k的svg文件。但对于其他图像格式，它工作得很好。