diff --git a/snap-overlay/bin/set-default-config.py b/snap-overlay/bin/set-default-config.py
index e3c195a..716033c 100755
--- a/snap-overlay/bin/set-default-config.py
+++ b/snap-overlay/bin/set-default-config.py
@@ -75,6 +75,9 @@ def _get_default_config():
         'config.nova.cpu-mode': 'host-model',
         # Do not override cpu-models by default.
         'config.nova.cpu-models': '',
+        # Allow up to an 8G image upload by default. This is quite large
+        # but should allow for some larger images by default (e.g. Windows)
+        'config.horizon.upload.max': '8G',
     }
 
 
diff --git a/snap-overlay/snap-openstack.yaml b/snap-overlay/snap-openstack.yaml
index 1d3a4f5..e2447bf 100644
--- a/snap-overlay/snap-openstack.yaml
+++ b/snap-overlay/snap-openstack.yaml
@@ -108,6 +108,7 @@ setup:
     dns_domain: 'config.network.dns-domain'
     dashboard_allowed_hosts: 'config.network.dashboard-allowed-hosts'
     dashboard_port: 'config.network.ports.dashboard'
+    max_upload_size: 'config.horizon.upload.max'
     mysql_port: 'config.network.ports.mysql'
     rabbit_port: 'config.network.ports.rabbit'
     logging_debug: 'config.logging.debug'
diff --git a/snap-overlay/templates/nginx.conf.j2 b/snap-overlay/templates/nginx.conf.j2
index 83155a8..f17f76f 100644
--- a/snap-overlay/templates/nginx.conf.j2
+++ b/snap-overlay/templates/nginx.conf.j2
@@ -15,6 +15,7 @@ http {
         tcp_nopush on;
         tcp_nodelay on;
         keepalive_timeout 65;
+        client_max_body_size {{ max_upload_size }};
         types_hash_max_size 2048;
 
         include {{ snap }}/usr/conf/mime.types;