Paperclip gem, Image has an extension that does not match its content - ruby-on-rails

Question

I am new to rails and have been following a tutorial on YouTube https://www.youtube.com/watch?v=70Pu_28yvdI and have gotten to around minute 40 and when I try to create a new post and attach an image I get an error Image has an extension that does not match its content, I coded the exact same code he did and keep getting the error. Thank you so much for the help.
post.rb file
class Post < ActiveRecord::Base
belongs_to :user
has_attached_file :image, styles: { medium: "700x500#", small: "350x250" }
validates_attachment_content_type :image, content_type: /\Aimage\/.*\Z/
end
post_controller.rb file
class PostsController < ApplicationController
before_action :find_post, only: [:show, :edit, :update, :destroy]
before_action :authenticate_user!, except: [:index, :show]
def index
#post = Post.all.order("created_at DESC")
end
def show
end
def new
#post = current_user.posts.build
end
def create
#post = current_user.posts.build(post_params)
if #post.save
redirect_to #post
else
render 'new'
end
end
def edit
end
def update
if #post.update(post_params)
redirect_to #post
else
render 'edit'
end
end
def destroy
#post.destroy
redirect_to root_path
end
private
def find_post
#post = Post.find(params[:id])
end
def post_params
params.require(:post).permit(:title, :link, :description, :image)
end
end
20150728130528_add_attachment_image_to_posts.rb file
class AddAttachmentImageToPosts < ActiveRecord::Migration
def self.up
change_table :posts do |t|
t.attachment :image
end
end
def self.down
remove_attachment :posts, :image
end
end

Answer 1

If you're on windows(from https://github.com/thoughtbot/paperclip):
If you're using Windows 7+ as a development environment, you may need
to install the file.exe application manually. The file spoofing system
in Paperclip 4+ relies on this; if you don't have it working, you'll
receive Validation failed: Upload file has an extension that does not
match its contents. errors.
Make sure you're using the same image type as you are validating:
You should ensure that you validate files to be only those MIME types
you explicitly want to support. If you don't, you could be open to XSS
attacks if a user uploads a file with a malicious HTML payload.
If you're only interested in images, restrict your allowed
content_types to image-y ones:
validates_attachment :avatar,
:content_type => { :content_type => ["image/jpeg", "image/gif", "image/png"] }
Paperclip::ContentTypeDetector will attempt to match a file's
extension to an inferred content_type, regardless of the actual
contents of the file.