diff --git a/group_vars/matrix_servers b/group_vars/matrix_servers
index 738c71ba7..fc3005f44 100755
--- a/group_vars/matrix_servers
+++ b/group_vars/matrix_servers
@@ -1995,7 +1995,7 @@ matrix_client_cinny_self_check_validate_certificates: "{{ false if matrix_ssl_re
 
 matrix_synapse_enabled: "{{ matrix_homeserver_implementation == 'synapse' }}"
 
-matrix_synapse_container_image_self_build: "{{ matrix_architecture not in ['arm64', 'amd64'] }}"
+matrix_synapse_container_image_self_build: "{{ matrix_architecture not in ['arm64', 'amd64'] or matrix_synapse_s3_media_store_enabled }}"
 
 # When ma1sd is enabled, we can use it to validate email addresses and phone numbers.
 # Synapse can validate email addresses by itself as well, but it's probably not what we want by default when we have an identity server.
diff --git a/roles/matrix-synapse/defaults/main.yml b/roles/matrix-synapse/defaults/main.yml
index 99391c7d4..77982db26 100644
--- a/roles/matrix-synapse/defaults/main.yml
+++ b/roles/matrix-synapse/defaults/main.yml
@@ -4,7 +4,7 @@
 
 matrix_synapse_enabled: true
 
-matrix_synapse_container_image_self_build: false
+matrix_synapse_container_image_self_build: "{{ matrix_synapse_s3_media_store_enabled }}"
 matrix_synapse_container_image_self_build_repo: "https://github.com/matrix-org/synapse.git"
 
 matrix_synapse_docker_image: "{{ matrix_synapse_docker_image_name_prefix }}matrixdotorg/synapse:{{ matrix_synapse_docker_image_tag }}"