diff --git a/out.go b/out.go
index 18ef4d7..93f296c 100644
--- a/out.go
+++ b/out.go
@@ -155,7 +155,7 @@ func copyFolder(roomFolder RoomFolder, outpath string) error {
 		transparent.Set(0, 0, color.RGBA{0xff, 0xff, 0xff, 0x01})
 
 		for _, imagename := range extraRequiredImages {
-			imagepath := path.Join(roomoutpath, imagename+".PNG")
+			imagepath := path.Join(roomoutpath, imagename+".png")
 
 			f, err := os.Create(imagepath)
 			if err != nil {
@@ -169,7 +169,7 @@ func copyFolder(roomFolder RoomFolder, outpath string) error {
 		log.Printf("INFO: necessary optional audios will use a silent file: %v", extraRequiredAudio)
 
 		for _, audioname := range extraRequiredAudio {
-			audiopath := path.Join(roomoutpath, audioname+".WAV")
+			audiopath := path.Join(roomoutpath, audioname+".wav")
 
 			err := os.WriteFile(audiopath, SILENCE_WAV, FILEPERM)
 			if err != nil {