diff --git a/Gemfile b/Gemfile
index ef744064b..ad1598af3 100644
--- a/Gemfile
+++ b/Gemfile
@@ -40,6 +40,7 @@ gem 'omniauth', '~> 1.2'
 
 gem 'doorkeeper', '~> 4.2'
 gem 'fast_blank', '~> 1.0'
+gem 'fastimage'
 gem 'goldfinger', '~> 2.1'
 gem 'hiredis', '~> 0.6'
 gem 'redis-namespace', '~> 1.5'
diff --git a/Gemfile.lock b/Gemfile.lock
index 8e4edb8e1..920262ede 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -185,6 +185,7 @@ GEM
     faraday (0.14.0)
       multipart-post (>= 1.2, < 3)
     fast_blank (1.0.0)
+    fastimage (2.1.1)
     ffi (1.9.18)
     fog-core (1.45.0)
       builder
@@ -641,6 +642,7 @@ DEPENDENCIES
   fabrication (~> 2.18)
   faker (~> 1.7)
   fast_blank (~> 1.0)
+  fastimage
   fog-core (~> 1.45)
   fog-local (~> 0.4)
   fog-openstack (~> 0.1)
diff --git a/app/lib/fast_geometry_parser.rb b/app/lib/fast_geometry_parser.rb
new file mode 100644
index 000000000..5209c2bc5
--- /dev/null
+++ b/app/lib/fast_geometry_parser.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class FastGeometryParser
+  def self.from_file(file)
+    width, height = FastImage.size(file.path)
+
+    raise Paperclip::Errors::NotIdentifiedByImageMagickError if width.nil?
+
+    Paperclip::Geometry.new(width, height)
+  end
+end
diff --git a/app/models/concerns/account_avatar.rb b/app/models/concerns/account_avatar.rb
index 53d0d876f..619644c9a 100644
--- a/app/models/concerns/account_avatar.rb
+++ b/app/models/concerns/account_avatar.rb
@@ -7,15 +7,9 @@ module AccountAvatar
 
   class_methods do
     def avatar_styles(file)
-      styles   = {}
-      geometry = Paperclip::Geometry.from_file(file)
-
-      styles[:original] = '120x120#' if geometry.width != geometry.height || geometry.width > 120 || geometry.height > 120
-      styles[:static]   = { format: 'png', convert_options: '-coalesce' } if file.content_type == 'image/gif'
-
+      styles = { original: { geometry: '120x120#', file_geometry_parser: FastGeometryParser } }
+      styles[:static] = { format: 'png', convert_options: '-coalesce', file_geometry_parser: FastGeometryParser } if file.content_type == 'image/gif'
       styles
-    rescue Paperclip::Errors::NotIdentifiedByImageMagickError
-      {}
     end
 
     private :avatar_styles
@@ -23,7 +17,7 @@ module AccountAvatar
 
   included do
     # Avatar upload
-    has_attached_file :avatar, styles: ->(f) { avatar_styles(f) }, convert_options: { all: '-strip' }
+    has_attached_file :avatar, styles: ->(f) { avatar_styles(f) }, convert_options: { all: '-strip' }, processors: [:lazy_thumbnail]
     validates_attachment_content_type :avatar, content_type: IMAGE_MIME_TYPES
     validates_attachment_size :avatar, less_than: 2.megabytes
   end
diff --git a/app/models/concerns/account_header.rb b/app/models/concerns/account_header.rb
index 991473d8c..5ed8a9c83 100644
--- a/app/models/concerns/account_header.rb
+++ b/app/models/concerns/account_header.rb
@@ -7,15 +7,9 @@ module AccountHeader
 
   class_methods do
     def header_styles(file)
-      styles   = {}
-      geometry = Paperclip::Geometry.from_file(file)
-
-      styles[:original] = '700x335#' unless geometry.width == 700 && geometry.height == 335
-      styles[:static]   = { format: 'png', convert_options: '-coalesce' } if file.content_type == 'image/gif'
-
+      styles = { original: { geometry: '700x335#', file_geometry_parser: FastGeometryParser } }
+      styles[:static] = { format: 'png', convert_options: '-coalesce', file_geometry_parser: FastGeometryParser } if file.content_type == 'image/gif'
       styles
-    rescue Paperclip::Errors::NotIdentifiedByImageMagickError
-      {}
     end
 
     private :header_styles
@@ -23,7 +17,7 @@ module AccountHeader
 
   included do
     # Header upload
-    has_attached_file :header, styles: ->(f) { header_styles(f) }, convert_options: { all: '-strip' }
+    has_attached_file :header, styles: ->(f) { header_styles(f) }, convert_options: { all: '-strip' }, processors: [:lazy_thumbnail]
     validates_attachment_content_type :header, content_type: IMAGE_MIME_TYPES
     validates_attachment_size :header, less_than: 2.megabytes
   end
diff --git a/app/models/media_attachment.rb b/app/models/media_attachment.rb
index b6e5916cb..38f88e9f7 100644
--- a/app/models/media_attachment.rb
+++ b/app/models/media_attachment.rb
@@ -32,7 +32,18 @@ class MediaAttachment < ApplicationRecord
   IMAGE_MIME_TYPES = ['image/jpeg', 'image/png', 'image/gif'].freeze
   VIDEO_MIME_TYPES = ['video/webm', 'video/mp4'].freeze
 
-  IMAGE_STYLES = { original: '1280x1280>', small: '400x400>' }.freeze
+  IMAGE_STYLES = {
+    original: {
+      geometry: '1280x1280>',
+      file_geometry_parser: FastGeometryParser,
+    },
+
+    small: {
+      geometry: '400x400>',
+      file_geometry_parser: FastGeometryParser,
+    },
+  }.freeze
+
   VIDEO_STYLES = {
     small: {
       convert_options: {
@@ -167,16 +178,16 @@ class MediaAttachment < ApplicationRecord
   end
 
   def image_geometry(file)
-    geo = Paperclip::Geometry.from_file file
+    width, height = FastImage.size(file.path)
+
+    return {} if width.nil?
 
     {
-      width:  geo.width.to_i,
-      height: geo.height.to_i,
-      size: "#{geo.width.to_i}x#{geo.height.to_i}",
-      aspect: geo.width.to_f / geo.height.to_f,
+      width:  width,
+      height: height,
+      size: "#{width}x#{height}",
+      aspect: width.to_f / height.to_f,
     }
-  rescue Paperclip::Errors::NotIdentifiedByImageMagickError
-    {}
   end
 
   def video_metadata(file)
diff --git a/app/models/preview_card.rb b/app/models/preview_card.rb
index 716b82243..86eecdfe5 100644
--- a/app/models/preview_card.rb
+++ b/app/models/preview_card.rb
@@ -33,7 +33,7 @@ class PreviewCard < ApplicationRecord
 
   has_and_belongs_to_many :statuses
 
-  has_attached_file :image, styles: { original: '400x400>' }, convert_options: { all: '-quality 80 -strip' }
+  has_attached_file :image, styles: { original: { geometry: '400x400>', file_geometry_parser: FastGeometryParser } }, convert_options: { all: '-quality 80 -strip' }
 
   include Attachmentable
   include Remotable
@@ -58,10 +58,11 @@ class PreviewCard < ApplicationRecord
 
     return if file.nil?
 
-    geo         = Paperclip::Geometry.from_file(file)
-    self.width  = geo.width.to_i
-    self.height = geo.height.to_i
-  rescue Paperclip::Errors::NotIdentifiedByImageMagickError
-    nil
+    width, height = FastImage.size(file.path)
+
+    return nil if width.nil?
+
+    self.width  = width
+    self.height = height
   end
 end
diff --git a/app/models/site_upload.rb b/app/models/site_upload.rb
index 8ffdc8313..641128adf 100644
--- a/app/models/site_upload.rb
+++ b/app/models/site_upload.rb
@@ -34,8 +34,8 @@ class SiteUpload < ApplicationRecord
 
     return if tempfile.nil?
 
-    geometry  = Paperclip::Geometry.from_file(tempfile)
-    self.meta = { width: geometry.width.to_i, height: geometry.height.to_i }
+    width, height = FastImage.size(tempfile.path)
+    self.meta = { width: width, height: height }
   end
 
   def clear_cache
diff --git a/config/application.rb b/config/application.rb
index 33981791e..cd180782c 100644
--- a/config/application.rb
+++ b/config/application.rb
@@ -7,6 +7,7 @@ require 'rails/all'
 Bundler.require(*Rails.groups)
 
 require_relative '../app/lib/exceptions'
+require_relative '../lib/paperclip/lazy_thumbnail'
 require_relative '../lib/paperclip/gif_transcoder'
 require_relative '../lib/paperclip/video_transcoder'
 require_relative '../lib/mastodon/snowflake'
diff --git a/lib/paperclip/lazy_thumbnail.rb b/lib/paperclip/lazy_thumbnail.rb
new file mode 100644
index 000000000..594f0ce39
--- /dev/null
+++ b/lib/paperclip/lazy_thumbnail.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+module Paperclip
+  class LazyThumbnail < Paperclip::Thumbnail
+    def make
+      return @file unless needs_convert?
+      Paperclip::Thumbnail.make(file, options, attachment)
+    end
+
+    private
+
+    def needs_convert?
+      needs_different_geometry? || needs_different_format?
+    end
+
+    def needs_different_geometry?
+      !@target_geometry.nil? && @current_geometry.width != @target_geometry.width && @current_geometry.height != @target_geometry.height
+    end
+
+    def needs_different_format?
+      @format.present? && @current_format != @format
+    end
+  end
+end