I've done the migration I have

```
has_attached_file :avatar, :styles => { :medium => "300x300>", :thumb => "100x100>" }, :default_url => "/images/missing/:style.png"

```

in my model, and im using

```
<%= form_for @user, :as => :user, :url => user_path, :html => { :multipart => true } do |form| %>
                <%= form.file_field :avatar %>
                <div class="actions">
                <%= form.submit %>
                </div>

```

To save the avatar uploaded and

```
<%= image_tag @user.avatar.url %>
<%= image_tag @user.avatar.url(:medium) %>
<%= image_tag @user.avatar.url(:thumb) %>

```

To display them all, but when I submit the new avatar it is not getting saved, I'm using 

```
@user = User.create(params[:user])

```

in the create so it should be saving, what could be the problem?

```
<%= form_for @user, :validate => true, :html => { :multipart => true } do |f|%>
  <div class="field">
    <%= f.label :username %><br />
    <%= f.text_field :username, :disabled => 'disabled' %><br />

    <%= f.label :full_name %><br />
    <%= f.text_field :full_name%><br />

    <%= f.label :email %><br />
    <%= f.text_field :email %>
  </div>

  <%= f.file_field :avatar %>

  <div class="actions">
    <%= f.submit "Update" %>
  </div>
<% end %>

ruby-1.9.2-p290 :002 > user = User.first
ruby-1.9.2-p290 :004 > user.avatar
=> /images/missing/original.png 

```

Nothing is getting changed 

```
avatar_file_name: nil, avatar_content_type: nil, avatar_file_size: nil, avatar_updated_at: nil>

```