Image holder is image upload and management tool for Rails.

It is light and does not do anything else than resizing and saving the image file.

In Gemfile, add

gem 'image_holder'

In your model do :

class YourModel < ActiveRecord::Base
  has_attached_image :ATTR_NAME, default: 'DEFAULT_IMAGE.png', scale: SIZE
end

• default: and scale: options are optional Example

Lets say you have a User model with attr name and logo

class User < ActiveRecord::Base
  attr_accessor :name, :logo
  
  has_attached_image :logo, default: 'default_user_logo.png', scale: 60
end

views/users/_form.html.erb

<%= form_for @user --- %>
----
----
<%= f.file_field :logo %>
----
----
<%= submit_tag %>

Nothing special, just usual

app/controllers/users_controller.rb

def create
---
---
  @user.save
---
---
end

Image will be located in

app/assets/images/users/logo<@user.id>.extension

The logo column in users table will store the path of image(logo in this example)

Inside view template do:

<%=  image_tag @user.logo %>