diff --git a/modules/04_base64.js b/modules/04_base64.js
index 53f40f5..58563aa 100644
--- a/modules/04_base64.js
+++ b/modules/04_base64.js
@@ -48,7 +48,8 @@ function Base64_encode_pass(input) {
 function Base64_decode(input) {
   var o = "";
   var c1 = 0, c2 = 0, c3 = 0, e1 = 0, e2 = 0, e3 = 0, e4 = 0;
-  input = input.replace(/[^\w\+\/\=]/g, "");
+  input = input.replace(/[^\w\+\/\=]/g, "")
+  .replace(/^data:.+\/.+;base64\,/,'');
   for (var i = 0; i < input.length; ) {
     e1 = Base64_map.indexOf(input.charAt(i++));
     e2 = Base64_map.indexOf(input.charAt(i++));
diff --git a/modules/04_base64.ts b/modules/04_base64.ts
index 154a446..295a553 100644
--- a/modules/04_base64.ts
+++ b/modules/04_base64.ts
@@ -40,7 +40,8 @@ function Base64_encode_pass(input: string): string {
 function Base64_decode(input: string): string {
 	var o = "";
 	var c1=0, c2=0, c3=0, e1=0, e2=0, e3=0, e4=0;
-	input = input.replace(/[^\w\+\/\=]/g, "");
+	input = input.replace(/[^\w\+\/\=]/g, "")
+	             .replace(/^data:.+\/.+;base64\,/,'');
 	for(var i = 0; i < input.length;) {
 		e1 = Base64_map.indexOf(input.charAt(i++));
 		e2 = Base64_map.indexOf(input.charAt(i++));