diff --git a/Tests/images/hopper_webp_bits.ppm b/Tests/images/hopper_webp_bits.ppm
index 6dce2da2e..f431bc7b1 100644
Binary files a/Tests/images/hopper_webp_bits.ppm and b/Tests/images/hopper_webp_bits.ppm differ
diff --git a/Tests/test_file_webp.py b/Tests/test_file_webp.py
index 06e274d0a..305abf481 100644
--- a/Tests/test_file_webp.py
+++ b/Tests/test_file_webp.py
@@ -16,8 +16,7 @@ class TestFileWebp(PillowTestCase):
             self.skipTest('WebP support not installed')
             return
 
-        # WebPAnimDecoder only returns RGBA or RGBX, never RGB
-        self.rgb_mode = "RGBX" if _webp.HAVE_WEBPANIM else "RGB"
+        self.rgb_mode = "RGB"
 
     def test_version(self):
         _webp.WebPDecoderVersion()
@@ -29,8 +28,7 @@ class TestFileWebp(PillowTestCase):
         Does it have the bits we expect?
         """
 
-        file_path = "Tests/images/hopper.webp"
-        image = Image.open(file_path)
+        image = Image.open("Tests/images/hopper.webp")
 
         self.assertEqual(image.mode, self.rgb_mode)
         self.assertEqual(image.size, (128, 128))
@@ -40,9 +38,7 @@ class TestFileWebp(PillowTestCase):
 
         # generated with:
         # dwebp -ppm ../../Tests/images/hopper.webp -o hopper_webp_bits.ppm
-        target = Image.open('Tests/images/hopper_webp_bits.ppm')
-        target = target.convert(self.rgb_mode)
-        self.assert_image_similar(image, target, 20.0)
+        self.assert_image_similar_tofile(image, 'Tests/images/hopper_webp_bits.ppm', 1.0)
 
     def test_write_rgb(self):
         """
@@ -61,13 +57,8 @@ class TestFileWebp(PillowTestCase):
         image.load()
         image.getdata()
 
-        # If we're using the exact same version of WebP, this test should pass.
-        # but it doesn't if the WebP is generated on Ubuntu and tested on
-        # Fedora.
-
         # generated with: dwebp -ppm temp.webp -o hopper_webp_write.ppm
-        # target = Image.open('Tests/images/hopper_webp_write.ppm')
-        # self.assert_image_equal(image, target)
+        self.assert_image_similar_tofile(image, 'Tests/images/hopper_webp_write.ppm', 12.0)
 
         # This test asserts that the images are similar. If the average pixel
         # difference between the two images is less than the epsilon value,
diff --git a/Tests/test_file_webp_lossless.py b/Tests/test_file_webp_lossless.py
index 10354c55f..4c35dad73 100644
--- a/Tests/test_file_webp_lossless.py
+++ b/Tests/test_file_webp_lossless.py
@@ -19,8 +19,7 @@ class TestFileWebpLossless(PillowTestCase):
         if (_webp.WebPDecoderVersion() < 0x0200):
             self.skipTest('lossless not included')
 
-        # WebPAnimDecoder only returns RGBA or RGBX, never RGB
-        self.rgb_mode = "RGBX" if _webp.HAVE_WEBPANIM else "RGB"
+        self.rgb_mode = "RGB"
 
     def test_write_lossless_rgb(self):
         temp_file = self.tempfile("temp.webp")
diff --git a/src/PIL/WebPImagePlugin.py b/src/PIL/WebPImagePlugin.py
index 39a8f2e35..1d8a0c10b 100644
--- a/src/PIL/WebPImagePlugin.py
+++ b/src/PIL/WebPImagePlugin.py
@@ -5,6 +5,7 @@ from io import BytesIO
 _VALID_WEBP_MODES = {
     "RGBX": True,
     "RGBA": True,
+    "RGB": True,
     }
 
 _VALID_WEBP_LEGACY_MODES = {
@@ -63,7 +64,8 @@ class WebPImageFile(ImageFile.ImageFile):
             bgcolor & 0xFF
         self.info["background"] = (bg_r, bg_g, bg_b, bg_a)
         self._n_frames = frame_count
-        self.mode = mode
+        self.mode = 'RGB' if mode == 'RGBX' else mode
+        self.rawmode = mode
         self.tile = []
 
         # Attempt to read ICC / EXIF / XMP chunks from file
@@ -154,7 +156,7 @@ class WebPImageFile(ImageFile.ImageFile):
 
                 # Set tile
                 self.fp = BytesIO(data)
-                self.tile = [("raw", (0, 0) + self.size, 0, self.mode)]
+                self.tile = [("raw", (0, 0) + self.size, 0, self.rawmode)]
 
         return super(WebPImageFile, self).load()
 
@@ -240,16 +242,23 @@ def _save_all(im, fp, filename):
 
                 # Make sure image mode is supported
                 frame = ims
+                rawmode = ims.mode
                 if ims.mode not in _VALID_WEBP_MODES:
-                    alpha = ims.mode == 'P' and 'A' in ims.im.getpalettemode()
-                    frame = ims.convert('RGBA' if alpha else 'RGBX')
+                    alpha = 'A' in ims.mode or 'a' in ims.mode \
+                            or ims.mode == 'P' and 'A' in ims.im.getpalettemode()
+                    rawmode = 'RGBA' if alpha else 'RGBX'
+                    frame = ims.convert(rawmode)
+
+                if rawmode == 'RGB':
+                    # For faster conversion, use RGBX
+                    rawmode = 'RGBX'
 
                 # Append the frame to the animation encoder
                 enc.add(
-                    frame.tobytes(),
+                    frame.tobytes('raw', rawmode),
                     timestamp,
                     frame.size[0], frame.size[1],
-                    frame.mode,
+                    rawmode,
                     lossless,
                     quality,
                     method
@@ -288,7 +297,8 @@ def _save(im, fp, filename):
     xmp = im.encoderinfo.get("xmp", "")
 
     if im.mode not in _VALID_WEBP_LEGACY_MODES:
-        alpha = im.mode == 'P' and 'A' in im.im.getpalettemode()
+        alpha = 'A' in im.mode or 'a' in im.mode \
+                or im.mode == 'P' and 'A' in im.im.getpalettemode()
         im = im.convert('RGBA' if alpha else 'RGB')
 
     data = _webp.WebPEncode(
diff --git a/src/_webp.c b/src/_webp.c
index f23d950f7..66b6d3268 100644
--- a/src/_webp.c
+++ b/src/_webp.c
@@ -216,6 +216,8 @@ PyObject* _anim_encoder_add(PyObject* self, PyObject* args)
         WebPPictureImportRGBA(frame, rgb, 4 * width);
     } else if (strcmp(mode, "RGBX")==0) {
         WebPPictureImportRGBX(frame, rgb, 4 * width);
+    } else {
+        WebPPictureImportRGB(frame, rgb, 3 * width);
     }
 
     // Add the frame to the encoder