diff --git a/maloja/apis/native_v1.py b/maloja/apis/native_v1.py
index 1e3cfab..41fa636 100644
--- a/maloja/apis/native_v1.py
+++ b/maloja/apis/native_v1.py
@@ -72,6 +72,14 @@ errors = {
 			'desc':"The database is being upgraded. Please try again later."
 		}
 	}),
+	images.MalformedB64: lambda e: (400,{
+		"status":"failure",
+		"error":{
+			'type':'malformed_b64',
+			'value':None,
+			'desc':"The provided base 64 string is not valid."
+		}
+	}),
 	# for http errors, use their status code
 	Exception: lambda e: ((e.status_code if hasattr(e,'statuscode') else 500),{
 		"status":"failure",
diff --git a/maloja/images.py b/maloja/images.py
index 8421d0c..f1c569a 100644
--- a/maloja/images.py
+++ b/maloja/images.py
@@ -267,6 +267,9 @@ def local_files(artist=None,artists=None,title=None):
 
 
 
+class MalformedB64(Exception):
+	pass
+
 def set_image(b64,**keys):
 	track = "title" in keys
 	if track:
@@ -279,7 +282,10 @@ def set_image(b64,**keys):
 	log("Trying to set image, b64 string: " + str(b64[:30] + "..."),module="debug")
 
 	regex = r"data:image/(\w+);base64,(.+)"
-	type,b64 = re.fullmatch(regex,b64).groups()
+	match = re.fullmatch(regex,b64)
+	if not match: raise MalformedB64()
+
+	type,b64 = match.groups()
 	b64 = base64.b64decode(b64)
 	filename = "webupload" + str(int(datetime.datetime.now().timestamp())) + "." + type
 	for folder in get_all_possible_filenames(**keys):
@@ -293,6 +299,7 @@ def set_image(b64,**keys):
 		with open(data_dir['images'](folder,filename),"wb") as f:
 			f.write(b64)
 
+
 	log("Saved image as " + data_dir['images'](folder,filename),module="debug")
 
 	# set as current picture in rotation