Add support for WebP and HEIC formats through conversion

app/javascript/mastodon/utils/resize_image.js

@@ -170,8 +170,10 @@ const resizeImage = (img, type = 'image/png') => new Promise((resolve, reject) =
     .catch(reject);
 });
 
+const WITHOUT_RESIZING_FORMATS = ['image/gif', 'image/heic', 'image/heif'];
+
 export default inputFile => new Promise((resolve) => {
-  if (!inputFile.type.match(/image.*/) || inputFile.type === 'image/gif') {
+  if (!inputFile.type.match(/image.*/) || WITHOUT_RESIZING_FORMATS.indexOf(inputFile.type) >= 0) {
     resolve(inputFile);
     return;
   }

app/models/media_attachment.rb

@@ -36,7 +36,7 @@ class MediaAttachment < ApplicationRecord
 
   MAX_DESCRIPTION_LENGTH = 1_500
 
-  IMAGE_FILE_EXTENSIONS = %w(.jpg .jpeg .png .gif).freeze
+  IMAGE_FILE_EXTENSIONS = %w(.jpg .jpeg .png .gif .webp .heif .heic).freeze
   VIDEO_FILE_EXTENSIONS = %w(.webm .mp4 .m4v .mov).freeze
   AUDIO_FILE_EXTENSIONS = %w(.ogg .oga .mp3 .wav .flac .opus .aac .m4a .3gp .wma).freeze
 
@@ -47,7 +47,8 @@ class MediaAttachment < ApplicationRecord
     small
   ).freeze
 
-  IMAGE_MIME_TYPES             = %w(image/jpeg image/png image/gif).freeze
+  IMAGE_MIME_TYPES             = %w(image/jpeg image/png image/gif image/webp image/heif image/heic).freeze
+  IMAGE_CONVERTIBLE_MIME_TYPES = %w(image/webp image/heif image/heic).freeze
   VIDEO_MIME_TYPES             = %w(video/webm video/mp4 video/quicktime video/ogg).freeze
   VIDEO_CONVERTIBLE_MIME_TYPES = %w(video/webm video/quicktime).freeze
   AUDIO_MIME_TYPES             = %w(audio/wave audio/wav audio/x-wav audio/x-pn-wave audio/ogg audio/mpeg audio/mp3 audio/webm audio/flac audio/aac audio/m4a audio/x-m4a audio/mp4 audio/3gpp video/x-ms-asf).freeze
@@ -290,6 +291,8 @@ class MediaAttachment < ApplicationRecord
         [:transcoder, :blurhash_transcoder, :type_corrector]
       elsif AUDIO_MIME_TYPES.include?(instance.file_content_type)
         [:image_extractor, :transcoder, :type_corrector]
+      elsif IMAGE_CONVERTIBLE_MIME_TYPES.include?(instance.file_content_type)
+        [:img_converter, :lazy_thumbnail, :blurhash_transcoder, :type_corrector]
       else
         [:lazy_thumbnail, :blurhash_transcoder, :type_corrector]
       end

lib/paperclip/img_converter.rb

@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+module Paperclip
+  class ImgConverter < Paperclip::Processor
+    def initialize(file, options = {}, attachment = nil)
+      super
+
+      @current_format = File.extname(@file.path)
+      @basename       = File.basename(@file.path, @current_format)
+    end
+
+    def make
+      dst_format, dst_content_type = opaque? ? ['jpg', 'image/jpeg'] : ['png', 'image/png']
+      dst_name = "#{@basename}.#{dst_format}"
+
+      attachment.instance.file_file_name = dst_name
+      attachment.instance.file_content_type = dst_content_type
+
+      options[:format] = dst_format
+      options[:content_type] = dst_content_type
+
+      dst = Paperclip::TempfileFactory.new.generate(dst_name)
+      convert(':src :dst', src: File.expand_path(@file.path), dst: File.expand_path(dst.path))
+
+      dst
+    end
+
+    private
+
+    def opaque?
+      identify('-format "%[opaque]" :src', src: File.expand_path(@file.path)).strip.downcase == 'true'
+    end
+  end
+end