diff --git a/qiita-markdown.gemspec b/qiita-markdown.gemspec
index 88c5540..5cd831c 100644
--- a/qiita-markdown.gemspec
+++ b/qiita-markdown.gemspec
@@ -25,6 +25,7 @@ Gem::Specification.new do |spec|
   spec.add_dependency "qiita_marker", "~> 0.23.9"
   spec.add_dependency "rouge", "~> 4.1.0"
   spec.add_dependency "sanitize"
+  spec.add_dependency "base64"
   spec.add_development_dependency "activesupport", "~> 5.2.7"
   spec.add_development_dependency "bundler"
   spec.add_development_dependency "codeclimate-test-reporter", "0.4.4"