diff --git a/homeassistant/components/image_processing/openalpr_cloud.py b/homeassistant/components/image_processing/openalpr_cloud.py
index 2fdc3d72f2e..dbf36dcd86e 100644
--- a/homeassistant/components/image_processing/openalpr_cloud.py
+++ b/homeassistant/components/image_processing/openalpr_cloud.py
@@ -109,12 +109,14 @@ class OpenAlprCloudEntity(ImageProcessingAlprEntity):
         websession = async_get_clientsession(self.hass)
         params = self._params.copy()
 
-        params['image_bytes'] = str(b64encode(image), 'utf-8')
+        body = {
+            'image_bytes': str(b64encode(image), 'utf-8')
+        }
 
         try:
             with async_timeout.timeout(self.timeout, loop=self.hass.loop):
                 request = yield from websession.post(
-                    OPENALPR_API_URL, params=params
+                    OPENALPR_API_URL, params=params, data=body
                 )
 
                 data = yield from request.json()
diff --git a/tests/components/image_processing/test_openalpr_cloud.py b/tests/components/image_processing/test_openalpr_cloud.py
index 40945f932c6..e840bce54f7 100644
--- a/tests/components/image_processing/test_openalpr_cloud.py
+++ b/tests/components/image_processing/test_openalpr_cloud.py
@@ -149,8 +149,7 @@ class TestOpenAlprCloud(object):
             'secret_key': "sk_abcxyz123456",
             'tasks': "plate",
             'return_image': 0,
-            'country': 'eu',
-            'image_bytes': "aW1hZ2U="
+            'country': 'eu'
         }
 
     def teardown_method(self):