diff --git a/example/sprites/subfolder/green.png b/example/sprites/subfolder/green.png
new file mode 100644
index 0000000..de8cbee
Binary files /dev/null and b/example/sprites/subfolder/green.png differ
diff --git a/index.js b/index.js
index 540aa81..b87ae62 100644
--- a/index.js
+++ b/index.js
@@ -46,7 +46,7 @@ try {
 function processFolder(folder) {
   fs.readdirSync(folder).forEach((file) => {
     if (fs.statSync(path.join(folder, file)).isDirectory()) {
-      processFolder(`${folder + file}/`)
+      processFolder(`${folder}/${file}/`)
     } else if (file.endsWith('.piskel')) {
       piskelToPNG(folder, file)
     } else if (file.endsWith('.png')) {