4 files changed, 17 insertions, 0 deletions
diff --git a/activestorage/CHANGELOG.md b/activestorage/CHANGELOG.md
index 54fc949172..d524ecf7d6 100644
--- a/activestorage/CHANGELOG.md
+++ b/activestorage/CHANGELOG.md
@@ -1,3 +1,7 @@
+*   Permit generating variants of BMP images.
+
+    *Younes Serraj*
+
 ## Rails 6.0.0.beta3 (March 11, 2019) ##
 
 *   No changes.
diff --git a/activestorage/lib/active_storage/engine.rb b/activestorage/lib/active_storage/engine.rb
index fc75a8f816..cbb205627e 100644
--- a/activestorage/lib/active_storage/engine.rb
+++ b/activestorage/lib/active_storage/engine.rb
@@ -33,6 +33,7 @@ module ActiveStorage
       image/jpeg
       image/pjpeg
       image/tiff
+      image/bmp
       image/vnd.adobe.photoshop
       image/vnd.microsoft.icon
     )
@@ -56,6 +57,7 @@ module ActiveStorage
       image/jpg
       image/jpeg
       image/tiff
+      image/bmp
       image/vnd.adobe.photoshop
       image/vnd.microsoft.icon
       application/pdf
diff --git a/activestorage/test/fixtures/files/colors.bmp b/activestorage/test/fixtures/files/colors.bmp
new file mode 100644
index 0000000000..3cc1e8764d
--- /dev/null
+++ b/activestorage/test/fixtures/files/colors.bmp
diff --git a/activestorage/test/models/variant_test.rb b/activestorage/test/models/variant_test.rb
index f6fa0e7afa..6b43923159 100644
--- a/activestorage/test/models/variant_test.rb
+++ b/activestorage/test/models/variant_test.rb
@@ -152,6 +152,17 @@ class ActiveStorage::VariantTest < ActiveSupport::TestCase
     assert_equal 33, image.height
   end
 
+  test "resized variation of BMP blob" do
+    blob = create_file_blob(filename: "colors.bmp")
+    variant = blob.variant(resize: "15x15").processed
+    assert_match(/colors\.bmp/, variant.service_url)
+
+    image = read_image(variant)
+    assert_equal "BMP", image.type
+    assert_equal 15, image.width
+    assert_equal 8, image.height
+  end
+
   test "optimized variation of GIF blob" do
     blob = create_file_blob(filename: "image.gif", content_type: "image/gif")