fix: update URL format in docker-compose and enhance error handling in http2pic class

docker-compose-dev.yml

@@ -1,4 +1,3 @@
-version: '3.3'
 services:
   http2pic:
     build:
@@ -13,6 +12,6 @@ services:
       - ./logs:/srv/logs
 
     environment:
-      - URL=http://localhostxxx:8080
+      - URL=http://localhost:8080
     ports:
       - 8080:80