diff --git a/html2doc.gemspec b/html2doc.gemspec
index 107c8f5..dcb7c9d 100644
--- a/html2doc.gemspec
+++ b/html2doc.gemspec
@@ -35,6 +35,7 @@ Gem::Specification.new do |spec|
   spec.add_dependency "thread_safe"
   spec.add_dependency "uuidtools"
   spec.add_dependency "unitsml"
+  spec.add_dependency "vectory", "~> 0.6"
 
   spec.add_development_dependency "debug"
   spec.add_development_dependency "equivalent-xml", "~> 0.6"
diff --git a/lib/html2doc/mime.rb b/lib/html2doc/mime.rb
index 16c2a27..64d70e9 100644
--- a/lib/html2doc/mime.rb
+++ b/lib/html2doc/mime.rb
@@ -1,8 +1,8 @@
 require "uuidtools"
 require "base64"
 require "mime/types"
-require "image_size"
 require "fileutils"
+require "vectory"
 
 class Html2Doc
   def mime_preamble(boundary, filename, result)
@@ -98,9 +98,9 @@ def image_cleanup(docxml, dir, localdir)
       local_filename = rename_image(i, dir, localdir)
       i["width"], i["height"] =
         if landscape?(i)
-          Metanorma::Utils.image_resize(i, local_filename, maxwidth, maxheight)
+          Vectory.image_resize(i, local_filename, maxwidth, maxheight)
         else
-          Metanorma::Utils.image_resize(i, local_filename, maxheight, maxwidth)
+          Vectory.image_resize(i, local_filename, maxheight, maxwidth)
         end
     end
     docxml