diff --git a/build.py b/build.py
index f044e027..60247f52 100755
--- a/build.py
+++ b/build.py
@@ -68,7 +68,7 @@ def loaderRaw(var):
 
 def loaderImage(var):
     fn = var.group(1)
-    return 'data:image/png;base64,{0}'.format(str(base64.encodestring(open(fn, 'rb').read())).replace('\n', ''))
+    return 'data:image/png;base64,{0}'.format(base64.encodestring(open(fn, 'rb').read()).decode('utf8').replace('\n', ''))
 
 def loadCode(ignore):
     return '\n\n'.join(map(readfile, glob.glob('code/*')))