diff --git a/app/assets/javascripts/discourse/lib/uploads.js.es6 b/app/assets/javascripts/discourse/lib/uploads.js.es6
index 0f12b3aa49..37ded98e4f 100644
--- a/app/assets/javascripts/discourse/lib/uploads.js.es6
+++ b/app/assets/javascripts/discourse/lib/uploads.js.es6
@@ -194,7 +194,7 @@ export function authorizesOneOrMoreImageExtensions(staff) {
 }
 
 export function isImage(path) {
-  return /\.(png|jpe?g|gif|svg|ico)$/i.test(path);
+  return /\.(png|webp|jpe?g|gif|svg|ico)$/i.test(path);
 }
 
 export function isVideo(path) {
diff --git a/lib/file_helper.rb b/lib/file_helper.rb
index c2fb8f6693..cbf11eebbe 100644
--- a/lib/file_helper.rb
+++ b/lib/file_helper.rb
@@ -133,7 +133,7 @@ class FileHelper
   end
 
   def self.supported_images
-    @@supported_images ||= Set.new %w{jpg jpeg png gif svg ico}
+    @@supported_images ||= Set.new %w{jpg jpeg png gif svg ico webp}
   end
 
   def self.supported_audio
diff --git a/spec/fixtures/images/tiff_as.bin b/spec/fixtures/images/tiff_as.bin
new file mode 100644
index 0000000000..dec1b3cfaa
Binary files /dev/null and b/spec/fixtures/images/tiff_as.bin differ
diff --git a/spec/lib/upload_creator_spec.rb b/spec/lib/upload_creator_spec.rb
index b2df27603e..6e796ea36f 100644
--- a/spec/lib/upload_creator_spec.rb
+++ b/spec/lib/upload_creator_spec.rb
@@ -79,12 +79,12 @@ RSpec.describe UploadCreator do
         expect(upload.original_filename).to eq('png_as.png')
       end
 
-      describe 'for webp format' do
+      describe 'for tiff format' do
         before do
-          SiteSetting.authorized_extensions = '.webp|.bin'
+          SiteSetting.authorized_extensions = '.tiff|.bin'
         end
 
-        let(:filename) { "webp_as.bin" }
+        let(:filename) { "tiff_as.bin" }
         let(:file) { file_from_fixtures(filename) }
 
         it 'should not correct the coerce filename' do
@@ -96,7 +96,7 @@ RSpec.describe UploadCreator do
 
           expect(upload.extension).to eq('bin')
           expect(File.extname(upload.url)).to eq('.bin')
-          expect(upload.original_filename).to eq('webp_as.bin')
+          expect(upload.original_filename).to eq('tiff_as.bin')
         end
       end
     end
diff --git a/test/javascripts/lib/uploads-test.js.es6 b/test/javascripts/lib/uploads-test.js.es6
index 1dbf5fde3f..0dfc71a4d7 100644
--- a/test/javascripts/lib/uploads-test.js.es6
+++ b/test/javascripts/lib/uploads-test.js.es6
@@ -123,7 +123,7 @@ QUnit.test("allows valid uploads to go through", assert => {
 });
 
 QUnit.test("isImage", assert => {
-  ["png", "jpg", "jpeg", "gif", "ico"].forEach(extension => {
+  ["png", "webp", "jpg", "jpeg", "gif", "ico"].forEach(extension => {
     var image = "image." + extension;
     assert.ok(isImage(image), image + " is recognized as an image");
     assert.ok(