diff --git a/app/models/user.rb b/app/models/user.rb
index a98a9ee..a2beb0a 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -16,6 +16,7 @@ class User < ApplicationRecord
   validates :full_name, presence: true
   validate :ensure_username_presence
   validates :avatar_border, inclusion: { in: ['white', 'black', 'none', 'rainbow', 'rainbow-overlay'] }
+  validates :avatar, format: { with: /\A(https?:\/\/).*\z/i, message: "must be a valid URL" }, allow_blank: true
 
   after_save :generate_open_graph_image, unless: -> { Rails.env.test? }
   after_save :download_and_store_avatar
@@ -39,27 +40,29 @@ def generate_open_graph_image
   end
 
   def download_and_store_avatar
-    return if avatar.blank? || !avatar.start_with?('http')
-  
+    return if avatar.blank?
+
     require 'open-uri'
     require 'fileutils'
-  
+
     begin
       avatar_dir = Rails.root.join('public', 'avatars')
       FileUtils.mkdir_p(avatar_dir) unless File.directory?(avatar_dir)
-  
+
       file = URI.open(avatar)
-  
+
       filename = "#{username}_avatar#{File.extname(avatar)}"
       filepath = File.join(avatar_dir, filename)
-  
+
       File.open(filepath, 'wb') do |local_file|
         local_file.write(file.read)
       end
-  
+
       Rails.logger.info "Avatar downloaded for user #{username}"
     rescue StandardError => e
       Rails.logger.error "Failed to download avatar for user #{username}: #{e.message}"
+      self.avatar = 'greg.jpg'  # Set to default avatar instead of nil
+      save(validate: false)  # Save without triggering validations
     end
   end
 
diff --git a/app/services/open_graph_image_generator.rb b/app/services/open_graph_image_generator.rb
index 29aae56..5006a89 100644
--- a/app/services/open_graph_image_generator.rb
+++ b/app/services/open_graph_image_generator.rb
@@ -1,3 +1,4 @@
+# app/services/open_graph_image_generator.rb
 class OpenGraphImageGenerator
   IMAGE_WIDTH = 1200
   IMAGE_HEIGHT = 630
@@ -12,7 +13,8 @@ def generate
     template_path = Rails.root.join('app', 'assets', 'images', 'og_template.png')
     output_path = Rails.root.join('public', 'uploads', 'og_images', "#{@user.username}_og.png")
     image = MiniMagick::Image.open(template_path)
-    avatar = download_image(@user.avatar)
+    
+    avatar = @user.avatar.present? ? download_image(@user.avatar) : default_avatar
 
     # Resize avatar and add a white square border
     avatar.resize "#{AVATAR_SIZE}x#{AVATAR_SIZE}"
@@ -60,11 +62,46 @@ def download_image(url)
       end
     rescue OpenURI::HTTPError, Errno::ENOENT, SocketError => e
       Rails.logger.error("Failed to download image from URL: #{url}. Error: #{e.message}. Using default image.")
-      # Use a default image if the download fails
-      default_image_path = Rails.root.join('app', 'assets', 'images', 'greg.jpg')
-      tempfile.write(File.read(default_image_path))
+      tempfile.write(File.read(default_avatar_path))
     end
     tempfile.rewind
     MiniMagick::Image.open(tempfile.path)
   end
+
+  def default_avatar
+    MiniMagick::Image.open(default_avatar_path)
+  end
+
+  def default_avatar_path
+    Rails.root.join('app', 'assets', 'images', 'greg.jpg')
+  end
 end
+
+# Console script to fix avatars and update open graph images
+def fix_avatars_and_update_og_images
+  User.where("avatar IS NOT NULL AND avatar != ''").each do |user|
+    puts "Processing user: #{user.username}"
+    
+    if !user.avatar.start_with?('http://', 'https://')
+      puts "  Invalid avatar URL, resetting to greg.jpg"
+      user.update_column(:avatar, 'greg.jpg')
+    end
+
+    begin
+      puts "  Downloading and storing avatar"
+      user.download_and_store_avatar
+
+      puts "  Generating open graph image"
+      OpenGraphImageGenerator.new(user).generate
+
+      puts "  Successfully processed user: #{user.username}"
+    rescue => e
+      puts "  Error processing user #{user.username}: #{e.message}"
+    end
+
+    puts "\n"  # Add a newline for readability between users
+  end
+end
+
+# Run the fix
+fix_avatars_and_update_og_images
\ No newline at end of file