src/java.desktop/share/classes/com/sun/imageio/plugins/gif/GIFImageWriter.java

@@ -1312,11 +1312,11 @@
 class GIFImageWriteParam extends ImageWriteParam {
     GIFImageWriteParam(Locale locale) {
         super(locale);
         this.canWriteCompressed = true;
         this.canWriteProgressive = true;
-        this.compressionTypes = new String[] {"LZW", "lzw"};
+        this.compressionTypes = new String[] {"LZW"};
         this.compressionType = compressionTypes[0];
     }
 
     public void setCompressionMode(int mode) {
         if (mode == MODE_DISABLED) {