diff --git a/app/logical/storage_manager.rb b/app/logical/storage_manager.rb
new file mode 100644
index 000000000..1ce833f88
--- /dev/null
+++ b/app/logical/storage_manager.rb
@@ -0,0 +1,106 @@
+class StorageManager
+  class Error < StandardError; end
+
+  DEFAULT_BASE_URL = Rails.application.routes.url_helpers.root_url + "data"
+  DEFAULT_BASE_DIR = "#{Rails.root}/public/data"
+
+  attr_reader :base_url, :base_dir, :hierarchical, :tagged_filenames, :large_image_prefix
+
+  def initialize(base_url: DEFAULT_BASE_URL, base_dir: DEFAULT_BASE_DIR, hierarchical: false, tagged_filenames: Danbooru.config.enable_seo_post_urls, large_image_prefix: Danbooru.config.large_image_prefix)
+    @base_url = base_url.chomp("/")
+    @base_dir = base_dir
+    @hierarchical = hierarchical
+    @tagged_filenames = tagged_filenames
+    @large_image_prefix = large_image_prefix
+  end
+
+  # Store the given file at the given path. If a file already exists at that
+  # location it should be overwritten atomically. Either the file is fully
+  # written, or an error is raised and the original file is left unchanged. The
+  # file should never be in a partially written state.
+  def store(io, path)
+    raise NotImplementedError, "store not implemented"
+  end
+
+  # Delete the file at the given path. If the file doesn't exist, no error
+  # should be raised.
+  def delete(path)
+    raise NotImplementedError, "delete not implemented"
+  end
+
+  # Return a readonly copy of the file located at the given path.
+  def open(path)
+    raise NotImplementedError, "open not implemented"
+  end
+
+  def store_file(io, post, type)
+    store(io, file_path(post.md5, post.file_ext, type))
+  end
+
+  def delete_file(post_id, md5, file_ext, type)
+    delete(file_path(md5, file_ext, type))
+  end
+
+  def open_file(post, type)
+    open(file_path(post.md5, post.file_ext, type))
+  end
+
+  def file_url(post, type)
+    subdir = subdir_for(post.md5)
+    file = file_name(post.md5, post.file_ext, type)
+
+    if type == :preview && !post.has_preview?
+      "#{base_url}/images/download-preview.png"
+    elsif type == :preview
+      "#{base_url}/preview/#{subdir}#{file}"
+    elsif type == :large && post.has_large?
+      "#{base_url}/sample/#{subdir}#{seo_tags(post)}#{file}"
+    else
+      "#{base_url}/#{subdir}#{seo_tags(post)}#{file}"
+    end
+  end
+
+  protected
+
+  def file_path(md5, file_ext, type)
+    subdir = subdir_for(md5)
+    file = file_name(md5, file_ext, type)
+
+    case type
+    when :preview
+      "#{base_dir}/preview/#{subdir}#{file}"
+    when :large
+      "#{base_dir}/sample/#{subdir}#{file}"
+    when :original
+      "#{base_dir}/#{subdir}#{file}"
+    end
+  end
+
+  def file_name(md5, file_ext, type)
+    large_file_ext = (file_ext == "zip") ? "webm" : "jpg"
+
+    case type
+    when :preview
+      "#{md5}.jpg"
+    when :large
+      "#{large_image_prefix}#{md5}.#{large_file_ext}"
+    when :original
+      "#{md5}.#{file_ext}"
+    end
+  end
+
+  def subdir_for(md5)
+    if hierarchical
+      "#{md5[0..1]}/#{md5[2..3]}/"
+    else
+      ""
+    end
+  end
+
+  def seo_tags(post, user = CurrentUser.user)
+    return "" if !tagged_filenames || user.disable_tagged_filenames?
+
+    tags = post.humanized_essential_tag_string.gsub(/[^a-z0-9]+/, "_").gsub(/(?:^_+)|(?:_+$)/, "").gsub(/_{2,}/, "_")
+    "__#{tags}__"
+  end
+end
diff --git a/app/logical/storage_manager/hybrid.rb b/app/logical/storage_manager/hybrid.rb
new file mode 100644
index 000000000..1e3afdda4
--- /dev/null
+++ b/app/logical/storage_manager/hybrid.rb
@@ -0,0 +1,23 @@
+class StorageManager::Hybrid < StorageManager
+  attr_reader :submanager
+
+  def initialize(&block)
+    @submanager = block
+  end
+
+  def store_file(io, post, type)
+    submanager[post.id, post.md5, post.file_ext, type].store_file(io, post, type)
+  end
+
+  def delete_file(post_id, md5, file_ext, type)
+    submanager[post_id, md5, file_ext, type].delete_file(post_id, md5, file_ext, type)
+  end
+
+  def open_file(io, post, type)
+    submanager[post.id, post.md5, post.file_ext, type].open_file(post, type)
+  end
+
+  def file_url(post, type)
+    submanager[post.id, post.md5, post.file_ext, type].file_url(post, type)
+  end
+end
diff --git a/app/logical/storage_manager/local.rb b/app/logical/storage_manager/local.rb
new file mode 100644
index 000000000..6bdfa69e3
--- /dev/null
+++ b/app/logical/storage_manager/local.rb
@@ -0,0 +1,25 @@
+class StorageManager::Local < StorageManager
+  DEFAULT_PERMISSIONS = 0644
+
+  def store(io, dest_path)
+    temp_path = dest_path + "-" + SecureRandom.uuid + ".tmp"
+
+    FileUtils.mkdir_p(File.dirname(temp_path))
+    bytes_copied = IO.copy_stream(io, temp_path)
+    raise Error, "store failed: #{bytes_copied}/#{io.size} bytes copied" if bytes_copied != io.size
+
+    FileUtils.chmod(DEFAULT_PERMISSIONS, temp_path)
+    File.rename(temp_path, dest_path)
+  rescue StandardError => e
+    FileUtils.rm_f(temp_path)
+    raise Error, e
+  end
+
+  def delete(path)
+    FileUtils.rm_f(path)
+  end
+
+  def open(path)
+    File.open(path, "r", binmode: true)
+  end
+end
diff --git a/app/logical/storage_manager/null.rb b/app/logical/storage_manager/null.rb
new file mode 100644
index 000000000..ebaeb8bfe
--- /dev/null
+++ b/app/logical/storage_manager/null.rb
@@ -0,0 +1,13 @@
+class StorageManager::Null < StorageManager
+  def store(io, path)
+    # no-op
+  end
+
+  def delete(path)
+    # no-op
+  end
+
+  def open(path)
+    # no-op
+  end
+end
diff --git a/app/logical/storage_manager/s3.rb b/app/logical/storage_manager/s3.rb
new file mode 100644
index 000000000..6549bf0bf
--- /dev/null
+++ b/app/logical/storage_manager/s3.rb
@@ -0,0 +1,43 @@
+class StorageManager::S3 < StorageManager
+  # https://docs.aws.amazon.com/sdkforruby/api/Aws/S3/Client.html#initialize-instance_method
+  DEFAULT_S3_OPTIONS = {
+    region: Danbooru.config.aws_region,
+    credentials: Danbooru.config.aws_credentials,
+    logger: Rails.logger,
+  }
+
+  # https://docs.aws.amazon.com/sdkforruby/api/Aws/S3/Client.html#put_object-instance_method
+  DEFAULT_PUT_OPTIONS = {
+    acl: "public-read",
+    storage_class: "STANDARD", # STANDARD, STANDARD_IA, REDUCED_REDUNDANCY
+    cache_control: "public, max-age=#{1.year.to_i}",
+    #content_type: "image/jpeg" # XXX should set content type
+  }
+
+  attr_reader :bucket, :client, :s3_options
+
+  def initialize(bucket, client: nil, s3_options: {}, **options)
+    @bucket = bucket
+    @s3_options = DEFAULT_S3_OPTIONS.merge(s3_options)
+    @client = client || Aws::S3::Client.new(**@s3_options)
+    super(**options)
+  end
+
+  def store(io, path)
+    data = io.read
+    base64_md5 = Digest::MD5.base64digest(data)
+    client.put_object(bucket: bucket, key: path, body: data, content_md5: base64_md5, **DEFAULT_PUT_OPTIONS)
+  end
+
+  def delete(path)
+    client.delete_object(bucket: bucket, key: path)
+  rescue Aws::S3::Errors::NoSuchKey
+    # ignore
+  end
+
+  def open(path)
+    file = Tempfile.new(binmode: true)
+    client.get_object(bucket: bucket: key: path, response_target: file)
+    file
+  end
+end
diff --git a/app/logical/storage_manager/sftp.rb b/app/logical/storage_manager/sftp.rb
new file mode 100644
index 000000000..add10d010
--- /dev/null
+++ b/app/logical/storage_manager/sftp.rb
@@ -0,0 +1,76 @@
+class StorageManager::SFTP < StorageManager
+  DEFAULT_PERMISSIONS = 0644
+
+  # http://net-ssh.github.io/net-ssh/Net/SSH.html#method-c-start
+  DEFAULT_SSH_OPTIONS = {
+    timeout: 10,
+    logger: Rails.logger,
+    verbose: :fatal,
+    non_interactive: true,
+  }
+
+  attr_reader :hosts, :ssh_options
+
+  def initialize(*hosts, ssh_options: {}, **options)
+    @hosts = hosts
+    @ssh_options = DEFAULT_SSH_OPTIONS.merge(ssh_options)
+    super(**options)
+  end
+
+  def store(file, dest_path)
+    temp_upload_path = dest_path + "-" + SecureRandom.uuid + ".tmp"
+    dest_backup_path = dest_path + "-" + SecureRandom.uuid + ".bak"
+
+    each_host do |host, sftp|
+      begin
+        sftp.upload!(file.path, temp_upload_path)
+        sftp.setstat!(temp_upload_path, permissions: DEFAULT_PERMISSIONS)
+
+        # `rename!` can't overwrite existing files, so if a file already exists
+        # at dest_path we move it out of the way first.
+        force { sftp.rename!(dest_path, dest_backup_path) }
+        force { sftp.rename!(temp_upload_path, dest_path) }
+      rescue StandardError => e
+        # if anything fails, try to move the original file back in place (if it was moved).
+        force { sftp.rename!(dest_backup_path, dest_path) }
+        raise Error, e
+      ensure
+        force { sftp.remove!(temp_upload_path) }
+        force { sftp.remove!(dest_backup_path) }
+      end
+    end
+  end
+
+  def delete(dest_path)
+    each_host do |host, sftp|
+      force { sftp.remove!(dest_path) }
+    end
+  end
+
+  def open(dest_path)
+    file = Tempfile.new(binmode: true)
+
+    Net::SFTP.start(hosts.first, nil, ssh_options) do |sftp|
+      sftp.download!(dest_path, file.path)
+    end
+
+    file
+  end
+
+  protected
+
+  # Ignore "no such file" exceptions for the given operation.
+  def force
+    yield
+  rescue Net::SFTP::StatusException => e
+    raise Error, e unless e.description == "no such file"
+  end
+
+  def each_host
+    hosts.each do |host|
+      Net::SFTP.start(host, nil, ssh_options) do |sftp|
+        yield host, sftp
+      end
+    end
+  end
+end
diff --git a/config/danbooru_default_config.rb b/config/danbooru_default_config.rb
index fd30ddc0c..a1bf74ff6 100644
--- a/config/danbooru_default_config.rb
+++ b/config/danbooru_default_config.rb
@@ -222,6 +222,41 @@ module Danbooru
       "danbooru"
     end
 
+    # The method to use for storing image files.
+    def storage_manager
+      # Store files on the local filesystem.
+      # base_dir - where to store files (default: under public/data)
+      # base_url - where to serve files from (default: http://#{hostname}/data)
+      # hierarchical: false - store files in a single directory
+      # hierarchical: true - store files in a hierarchical directory structure, based on the MD5 hash
+      StorageManager::Local.new(base_dir: "#{Rails.root}/public/data", hierarchical: false)
+
+      # Store files on one or more remote host(s). Configure SSH settings in
+      # ~/.ssh_config or in the ssh_options param (ref: http://net-ssh.github.io/net-ssh/Net/SSH.html#method-c-start)
+      # StorageManager::SFTP.new("i1.example.com", "i2.example.com", base_dir: "/mnt/backup", hierarchical: false, ssh_options: {})
+
+      # Store files in an S3 bucket. The bucket must already exist and be
+      # writable by you. Configure your S3 settings in aws_region and
+      # aws_credentials below, or in the s3_options param (ref:
+      # https://docs.aws.amazon.com/sdkforruby/api/Aws/S3/Client.html#initialize-instance_method)
+      # StorageManager::S3.new("my_s3_bucket", base_url: "https://my_s3_bucket.s3.amazonaws.com/", s3_options: {})
+
+      # Select the storage method based on the post's id and type (preview, large, or original).
+      # StorageManager::Hybrid.new do |id, md5, file_ext, type|
+      #   ssh_options = { user: "danbooru" }
+      #
+      #   if type.in?([:large, :original]) && id.in?(0..850_000)
+      #     StorageManager::SFTP.new("raikou1.donmai.us", base_url: "https://raikou1.donmai.us", base_dir: "/path/to/files", hierarchical: true, ssh_options: ssh_options)
+      #   elsif type.in?([:large, :original]) && id.in?(850_001..2_000_000)
+      #     StorageManager::SFTP.new("raikou2.donmai.us", base_url: "https://raikou2.donmai.us", base_dir: "/path/to/files", hierarchical: true, ssh_options: ssh_options)
+      #   elsif type.in?([:large, :original]) && id.in?(2_000_001..3_000_000)
+      #     StorageManager::SFTP.new(*all_server_hosts, base_url: "https://hijiribe.donmai.us/data", ssh_options: ssh_options)
+      #   else
+      #     StorageManager::SFTP.new(*all_server_hosts, ssh_options: ssh_options)
+      #   end
+      # end
+    end
+
     def build_file_url(post)
       "/data/#{post.file_path_prefix}/#{post.md5}.#{post.file_ext}"
     end
@@ -611,6 +646,14 @@ module Danbooru
     end
 
     # AWS config options
+    def aws_region
+      "us-east-1"
+    end
+
+    def aws_credentials
+      Aws::Credentials.new(Danbooru.config.aws_access_key_id, Danbooru.config.aws_secret_access_key)
+    end
+
     def aws_access_key_id
     end
 
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 04a3d3edd..19474ca49 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -38,6 +38,9 @@ class ActiveSupport::TestCase
     mock_missed_search_service!
     WebMock.allow_net_connect!
     Danbooru.config.stubs(:enable_sock_puppet_validation?).returns(false)
+
+    storage_manager = StorageManager::Local.new(base_dir: "#{Rails.root}/public/data/test")
+    Danbooru.config.stubs(:storage_manager).returns(storage_manager)
   end
 
   teardown do