你好，我在显示图片时遇到如下问题： wrong number of arguments (given 1, expected 0)

Extracted source (around line #18):

<%= @course.course_introduction %> 18 <%= image_tag(@course.avatar(:lb)) %>

Rails.root: /home/stormand/RubymineProjects/CourseSelect Application Trace | Framework Trace | Full Trace

app/views/courses/detail.erb:18:in `app_views_courses_detail_erb_3528013227028476933_69855157661360'

Request

Parameters:

{"id"=>"1"}

为什么添加 (:lb) 版本号后就会报错啊？如果删去 (:lb) 就没有问题。 uploader 中也定义了版本