--- a/includes/Linker.php	
+++ a/includes/Linker.php	
@@ -773,31 +773,31 @@ class Linker {
 	 * Make a "broken" link to an image
 	 *
 	 * @param $title Title object
-	 * @param $text String: link label in unescaped text form
+	 * @param $label String: link label (plain text)
 	 * @param $query String: query string
-	 * @param $trail String: link trail (HTML fragment)
-	 * @param $prefix String: link prefix (HTML fragment)
+	 * @param $unused1 Unused parameter kept for b/c
+	 * @param $unused2 Unused parameter kept for b/c
 	 * @param $time Boolean: a file of a certain timestamp was requested
 	 * @return String
 	 */
-	public static function makeBrokenImageLinkObj( $title, $text = '', $query = '', $trail = '', $prefix = '', $time = false ) {
+	public static function makeBrokenImageLinkObj( $title, $label = '', $query = '', $unused1 = '', $unused2 = '', $time = false ) {
 		global $wgEnableUploads, $wgUploadMissingFileUrl;
 		if ( ! $title instanceof Title ) {
-			return "<!-- ERROR -->{$prefix}{$text}{$trail}";
+			return "<!-- ERROR -->" . htmlspecialchars( $label );
 		}
 		wfProfileIn( __METHOD__ );
+		if ( $label == '' ) {
+			$label = $title->getPrefixedText();
+		}
+		$encLabel = htmlspecialchars( $label );
 		$currentExists = $time ? ( wfFindFile( $title ) != false ) : false;
 
-		list( $inside, $trail ) = self::splitTrail( $trail );
-		if ( $text == '' )
-			$text = htmlspecialchars( $title->getPrefixedText() );
-
 		if ( ( $wgUploadMissingFileUrl || $wgEnableUploads ) && !$currentExists ) {
 			$redir = RepoGroup::singleton()->getLocalRepo()->checkRedirect( $title );
 
 			if ( $redir ) {
 				wfProfileOut( __METHOD__ );
-				return self::linkKnown( $title, "$prefix$text$inside", array(), $query ) . $trail;
+				return self::linkKnown( $title, $encLabel, array(), wfCgiToArray( $query ) );
 			}
 
 			$href = self::getUploadUrl( $title, $query );
@@ -805,10 +805,10 @@ class Linker {
 			wfProfileOut( __METHOD__ );
 			return '<a href="' . htmlspecialchars( $href ) . '" class="new" title="' .
 				htmlspecialchars( $title->getPrefixedText(), ENT_QUOTES ) . '">' .
-				"$prefix$text$inside</a>$trail";
+				$encLabel . '</a>';
 		} else {
 			wfProfileOut( __METHOD__ );
-			return self::linkKnown( $title, "$prefix$text$inside", array(), $query ) . $trail;
+			return self::linkKnown( $title, $encLabel, array(), wfCgiToArray( $query ) );
 		}
 	}
 
--- a/tests/parser/parserTests.txt	
+++ a/tests/parser/parserTests.txt	
@@ -1666,6 +1666,21 @@ Link with double quotes in title part (literal) and alternate part (interpreted)
 !! end
 
 !! test
+Broken image links with HTML captions (bug 39700)
+!! input
+[[File:Nonexistent|<script></script>]]
+[[File:Nonexistent|100px|<script></script>]]
+[[File:Nonexistent|&lt;]]
+[[File:Nonexistent|a<i>b</i>c]]
+!! result
+<p><a href="/index.php?title=Special:Upload&amp;wpDestFile=Nonexistent" class="new" title="File:Nonexistent">&lt;script&gt;&lt;/script&gt;</a>
+<a href="/index.php?title=Special:Upload&amp;wpDestFile=Nonexistent" class="new" title="File:Nonexistent">&lt;script&gt;&lt;/script&gt;</a>
+<a href="/index.php?title=Special:Upload&amp;wpDestFile=Nonexistent" class="new" title="File:Nonexistent">&lt;</a>
+<a href="/index.php?title=Special:Upload&amp;wpDestFile=Nonexistent" class="new" title="File:Nonexistent">abc</a>
+</p>
+!! end
+
+!! test
 Plain link to URL
 !! input
 [[http://www.example.com]]