diff --git a/lib/tasks/openfarm.rake b/lib/tasks/openfarm.rake
index 92ca9cc39..6268df6c9 100644
--- a/lib/tasks/openfarm.rake
+++ b/lib/tasks/openfarm.rake
@@ -8,4 +8,13 @@ namespace :openfarm do
     Rails.logger = Logger.new(STDOUT)
     OpenfarmService.new.import!
   end
+
+  desc "Delete all pictures with source OpenFarm"
+  task delete_pictures: :environment do
+    puts "Deleting pictures with source OpenFarm..."
+    photos_to_delete = Photo.where(source: 'OpenFarm')
+    count = photos_to_delete.count
+    photos_to_delete.destroy_all
+    puts "Deleted #{count} pictures."
+  end
 end
diff --git a/spec/tasks/openfarm_rake_spec.rb b/spec/tasks/openfarm_rake_spec.rb
new file mode 100644
index 000000000..56681a43e
--- /dev/null
+++ b/spec/tasks/openfarm_rake_spec.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+require 'rake'
+
+describe 'openfarm:delete_pictures' do
+  before(:all) do
+    Rails.application.load_tasks
+  end
+
+  # We need to do this because Rake tasks normally output to STDOUT, but we
+  # don't want to clutter up the test output.
+  before(:each) do
+    $stdout = StringIO.new
+  end
+
+  after(:each) do
+    $stdout = STDOUT
+  end
+
+  it 'deletes pictures with source OpenFarm' do
+    create(:photo, source: 'OpenFarm')
+    create(:photo, source: 'flickr')
+
+    expect(Photo.where(source: 'OpenFarm').count).to eq(1)
+    expect(Photo.where(source: 'flickr').count).to eq(1)
+
+    Rake::Task['openfarm:delete_pictures'].invoke
+
+    expect(Photo.where(source: 'OpenFarm').count).to eq(0)
+    expect(Photo.where(source: 'flickr').count).to eq(1)
+  end
+end