diff --git a/Containerfile b/Containerfile
index b46c8ae..aaec259 100644
--- a/Containerfile
+++ b/Containerfile
@@ -29,6 +29,7 @@ RUN \
 	apk add --no-cache \
 		python3 \
 		py3-lxml \
+		libmagic \
 		tzdata && \
   echo "" && \
 	echo "**** install pip dependencies ****" && \
diff --git a/maloja/server.py b/maloja/server.py
index c76d9a9..35ae5b3 100644
--- a/maloja/server.py
+++ b/maloja/server.py
@@ -3,6 +3,7 @@ import os
 from threading import Thread
 from importlib import resources
 import time
+from magic import from_file
 
 
 # server stuff
@@ -154,7 +155,8 @@ def static_image(pth):
 
 @webserver.route("/cacheimages/<uuid>")
 def static_proxied_image(uuid):
-	return static_file(uuid,root=data_dir['cache']('images'))
+	mimetype = from_file(os.path.join(data_dir['cache']('images'),uuid),True)
+	return static_file(uuid,root=data_dir['cache']('images'),mimetype=mimetype)
 
 @webserver.route("/login")
 def login():
diff --git a/requirements.txt b/requirements.txt
index e81dd5d..ffb17a3 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -8,6 +8,7 @@ lru-dict==1.3.*
 psutil==5.9.*
 sqlalchemy==2.0
 python-datauri==3.0.*
+python-magic==0.4.*
 requests==2.32.*
 toml==0.10.*
 PyYAML==6.0.*