diff --git a/min/lib/Minify/CSS/UriRewriter.php b/min/lib/Minify/CSS/UriRewriter.php
index 8845f15..50360ce 100644
--- a/min/lib/Minify/CSS/UriRewriter.php
+++ b/min/lib/Minify/CSS/UriRewriter.php
@@ -282,11 +282,8 @@ class Minify_CSS_UriRewriter {
                 ? $m[1]
                 : substr($m[1], 1, strlen($m[1]) - 2);
         }
-        // analyze URI
-        if ('/' !== $uri[0]                  // root-relative
-            && false === strpos($uri, '//')  // protocol (non-data)
-            && 0 !== strpos($uri, 'data:')   // data protocol
-        ) {
+        // if not root/scheme relative and not starts with scheme
+        if (!preg_match('~^(/|[a-z]+\:)~', $uri)) {
             // URI is file-relative: rewrite depending on options
             if (self::$_prependPath === null) {
                 $uri = self::rewriteRelative($uri, self::$_currentDir, self::$_docRoot, self::$_symlinks);
diff --git a/min_unit_tests/_test_files/css_uriRewriter/exp.css b/min_unit_tests/_test_files/css_uriRewriter/exp.css
index d749295..bd6d69e 100644
--- a/min_unit_tests/_test_files/css_uriRewriter/exp.css
+++ b/min_unit_tests/_test_files/css_uriRewriter/exp.css
@@ -3,12 +3,12 @@
 @import '/_test_files/bar/foo.css' print;
 @import '/foo.css' print;
 @import '/css/foo.css'; /* abs, should not alter */
-@import 'http://foo.com/css/foo.css'; /* abs, should not alter */
+@import 'http://foo.com/css/foo.css'; /* scheme, should not alter */
 @import url(/_test_files/foo.css) tv, projection;
 @import url("/css/foo.css"); /* abs, should not alter */
 @import url(/css2/foo.css); /* abs, should not alter */
-@import url(data:image/gif;base64,AAAA); /* data, should not alter */
+@import url(foo:bar); /* scheme, should not alter */
 foo {background:url('/_test_files/css_uriRewriter/bar/foo.png')}
-foo {background:url('http://foo.com/css/foo.css');} /* abs, should not alter */
+foo {background:url('http://foo.com/css/foo.css');} /* scheme, should not alter */
 foo {background:url("//foo.com/css/foo.css");} /* protocol relative, should not alter */
-foo {background:url(data:image/gif;base64,AAAA);} /* data, should not alter */
\ No newline at end of file
+foo {background:url(foo:bar);} /* scheme, should not alter */
diff --git a/min_unit_tests/_test_files/css_uriRewriter/exp_prepend.css b/min_unit_tests/_test_files/css_uriRewriter/exp_prepend.css
index 87b7ecb..d00cd35 100644
--- a/min_unit_tests/_test_files/css_uriRewriter/exp_prepend.css
+++ b/min_unit_tests/_test_files/css_uriRewriter/exp_prepend.css
@@ -3,12 +3,12 @@
 @import 'http://cnd.com/A/bar/foo.css' print;
 @import 'http://cnd.com/foo.css' print;
 @import '/css/foo.css'; /* abs, should not alter */
-@import 'http://foo.com/css/foo.css'; /* abs, should not alter */
+@import 'http://foo.com/css/foo.css'; /* scheme, should not alter */
 @import url(http://cnd.com/A/foo.css) tv, projection;
 @import url("/css/foo.css"); /* abs, should not alter */
 @import url(/css2/foo.css); /* abs, should not alter */
-@import url(data:image/gif;base64,AAAA); /* data, should not alter */
+@import url(foo:bar); /* scheme, should not alter */
 foo {background:url('http://cnd.com/A/B/bar/foo.png')}
-foo {background:url('http://foo.com/css/foo.css');} /* abs, should not alter */
+foo {background:url('http://foo.com/css/foo.css');} /* scheme, should not alter */
 foo {background:url("//foo.com/css/foo.css");} /* protocol relative, should not alter */
-foo {background:url(data:image/gif;base64,AAAA);} /* data, should not alter */
\ No newline at end of file
+foo {background:url(foo:bar);} /* scheme, should not alter */
diff --git a/min_unit_tests/_test_files/css_uriRewriter/exp_prepend2.css b/min_unit_tests/_test_files/css_uriRewriter/exp_prepend2.css
index ceea4ec..55badf5 100644
--- a/min_unit_tests/_test_files/css_uriRewriter/exp_prepend2.css
+++ b/min_unit_tests/_test_files/css_uriRewriter/exp_prepend2.css
@@ -3,12 +3,12 @@
 @import '//cnd.com/A/bar/foo.css' print;
 @import '//cnd.com/foo.css' print;
 @import '/css/foo.css'; /* abs, should not alter */
-@import 'http://foo.com/css/foo.css'; /* abs, should not alter */
+@import 'http://foo.com/css/foo.css'; /* scheme, should not alter */
 @import url(//cnd.com/A/foo.css) tv, projection;
 @import url("/css/foo.css"); /* abs, should not alter */
 @import url(/css2/foo.css); /* abs, should not alter */
-@import url(data:image/gif;base64,AAAA); /* data, should not alter */
+@import url(foo:bar); /* scheme, should not alter */
 foo {background:url('//cnd.com/A/B/bar/foo.png')}
-foo {background:url('http://foo.com/css/foo.css');} /* abs, should not alter */
+foo {background:url('http://foo.com/css/foo.css');} /* scheme, should not alter */
 foo {background:url("//foo.com/css/foo.css");} /* protocol relative, should not alter */
-foo {background:url(data:image/gif;base64,AAAA);} /* data, should not alter */
\ No newline at end of file
+foo {background:url(foo:bar);} /* scheme, should not alter */
diff --git a/min_unit_tests/_test_files/css_uriRewriter/in.css b/min_unit_tests/_test_files/css_uriRewriter/in.css
index aa41d0a..3497b87 100644
--- a/min_unit_tests/_test_files/css_uriRewriter/in.css
+++ b/min_unit_tests/_test_files/css_uriRewriter/in.css
@@ -3,12 +3,12 @@
 @import '../bar/foo.css' print;
 @import '../../foo.css' print;
 @import '/css/foo.css'; /* abs, should not alter */
-@import 'http://foo.com/css/foo.css'; /* abs, should not alter */
+@import 'http://foo.com/css/foo.css'; /* scheme, should not alter */
 @import url(../foo.css) tv, projection;
 @import url("/css/foo.css"); /* abs, should not alter */
 @import url(/css2/foo.css); /* abs, should not alter */
-@import url(data:image/gif;base64,AAAA); /* data, should not alter */
+@import url(foo:bar); /* scheme, should not alter */
 foo {background:url('bar/foo.png')}
-foo {background:url('http://foo.com/css/foo.css');} /* abs, should not alter */
+foo {background:url('http://foo.com/css/foo.css');} /* scheme, should not alter */
 foo {background:url("//foo.com/css/foo.css");} /* protocol relative, should not alter */
-foo {background:url(data:image/gif;base64,AAAA);} /* data, should not alter */
\ No newline at end of file
+foo {background:url(foo:bar);} /* scheme, should not alter */