diff --git a/cmd/cory-bin/main.go b/cmd/cory-bin/main.go
index db8d99d..57e5077 100644
--- a/cmd/cory-bin/main.go
+++ b/cmd/cory-bin/main.go
@@ -48,7 +48,11 @@ func main() {
 			printIf("could not find file %s\n", filename)
 			return
 		}
-		dump(filename, output)
+		err := dump(filename, output)
+		if err != nil {
+			fmt.Println(err)
+			return
+		}
 		return
 	}
 	flag.PrintDefaults()
@@ -60,25 +64,26 @@ func printIf(s string, args ...interface{}) {
 	}
 }
 
-func dump(filename string, output string) {
+func dump(filename string, output string) error {
 	start := time.Now()
 	printIf("reading file '%s'\n", filename)
 	n, err := nori.FromFile(filename)
 	if err != nil {
-		log.Panicf("decode: %s", err)
+		return fmt.Errorf("decode: %w", err)
 	}
 	out := new(bytes.Buffer)
 	printIf("rendering %d animation(s)\n", n.AnimationCount)
 	animations, err := renderer.RenderAnimationsApng(n)
 	if err != nil {
-		log.Panicf("animation: %s\n", err)
+		return fmt.Errorf("animation: %w", err)
 	}
 	printIf("saving to %s \n", output)
 	if err := utils.ZipApngs(out, animations); err != nil {
-		log.Panicf("zipping: %s\n", err)
+		return fmt.Errorf("zipping: %w", err)
 	}
 	printIf("done in %v \n", time.Now().Sub(start))
 	os.WriteFile(output, out.Bytes(), 0740)
+	return nil
 }
 
 func serve() {
@@ -92,7 +97,7 @@ func serve() {
 	r.Use(middleware.Timeout(60 * time.Second))
 
 	r.Post("/animations", func(w http.ResponseWriter, r *http.Request) {
-		output_type := chi.URLParam(r, "format")
+		output_type := r.URL.Query().Get("format")
 		switch output_type {
 		case "":
 			output_type = "apng"