diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,3 +15,8 @@
 ## 0.1.2.2 -- 2020-05-22
 
 * Support for OSC1337
+
+## 0.1.2.32 -- 2020-05-25
+
+* Use the palette of 256 colors to fix not working on xterm.
+* Change from convert(imagemagick) to gs(ghostscript), because convert does not work on ubuntu18.04.
diff --git a/csrc/sixel.c b/csrc/sixel.c
--- a/csrc/sixel.c
+++ b/csrc/sixel.c
@@ -113,3 +113,73 @@
   return p;
 }
 
+
+int
+img2palettized_sixel(unsigned char* buf, unsigned char* img, unsigned char* colors,int width,int height){
+  int i,j,k;
+  int p=0;
+  int c;
+  int prev = -1;
+  buf[p++] = 033;  // ESC
+  buf[p++] = 'P';
+  buf[p++] = '8';
+  buf[p++] = ';';
+  buf[p++] = '1';
+  buf[p++] = ';';
+  buf[p++] = '0';
+  buf[p++] = 'q';
+  buf[p++] = '"';
+  buf[p++] = '1';
+  buf[p++] = ';';
+  buf[p++] = '1';
+  buf[p++] = ';';
+  putnum(buf,&p,width);
+  buf[p++] = ';';
+  putnum(buf,&p,height);
+  for(i=0;i<256;i++){
+    buf[p++] = '#';
+    putnum(buf,&p,i);
+    buf[p++] = ';';
+    buf[p++] = '2';
+    buf[p++] = ';';
+    putnum(buf,&p,colors[i*3]*101/256);
+    buf[p++] = ';';
+    putnum(buf,&p,colors[i*3+1]*101/256);
+    buf[p++] = ';';
+    putnum(buf,&p,colors[i*3+2]*101/256);
+  }
+  for(j=0;j<height;j++){
+    for(i=0;i<width;i++){
+      int cur = img[j*width+i];
+      if (prev != cur){
+	buf[p++] = '#';
+	putnum(buf,&p,cur);
+      } else {
+      	int num;
+      	for(k=i+1;k<width;k++){
+      	  int nxt = img[j*width+k];
+      	  if(nxt!=cur){
+      	    break;
+      	  }
+      	}
+      	num = (k-i)-1;
+      	if(num > 3){
+      	  buf[p++] = '!';
+      	  putnum(buf,&p,num+1);
+      	  i=k-1;
+      	}
+      }
+      buf[p++] = (1 << (j%6))+0x3f;
+      prev = cur;
+    }
+    if(j%6 ==5){
+      buf[p++] = '-'; // LR
+    }else{
+      buf[p++] = '$'; // CR
+    }
+  }
+  buf[p++] = 033;  // END
+  buf[p++] = '\\'; // END
+  return p;
+}
+
diff --git a/sixel.cabal b/sixel.cabal
--- a/sixel.cabal
+++ b/sixel.cabal
@@ -1,6 +1,6 @@
 cabal-version:       >=1.10
 name:                sixel
-version:             0.1.2.2
+version:             0.1.2.3
 synopsis:            Sixel library to show images in a terminal emulator
 description:         Sixel can show graphics on a terminal emulator. This library is developed to showing images on ghci.
 license:             BSD3
diff --git a/src/Data/Sixel.hs b/src/Data/Sixel.hs
--- a/src/Data/Sixel.hs
+++ b/src/Data/Sixel.hs
@@ -88,8 +88,8 @@
   putSixel img = putSixel $ convertRGB8 img
 
 instance {-# OVERLAPS #-} ToSixel (Image PixelRGB8) where
-  toSixel img = SixelImage (BC.unpack $ img2sixel img)
-  putSixel img = BC.putStr $ img2sixel img
+  toSixel img = SixelImage (BC.unpack $ img2palettizedSixel img)
+  putSixel img = BC.putStr $ img2palettizedSixel img
 
 instance {-# OVERLAPS #-} ToSixel SixelImage where
   toSixel = id
@@ -158,6 +158,20 @@
     withForeignPtr sptr $ \src -> do
       len <- c_img2sixel (castPtr dst) (castPtr src) (fromIntegral w) (fromIntegral h)
       return (fromIntegral len)
+
+img2palettizedSixel :: Image PixelRGB8 -> ByteString
+img2palettizedSixel img = unsafePerformIO $ do
+  let (img',palette) = palettize (PaletteOptions MedianMeanCut True 256) img
+      (Image w h vec) = img'
+      (Image _ _ p) = palette
+  bsize <- c_bufsize (fromIntegral w) (fromIntegral h)
+  let (sptr, _) = V.unsafeToForeignPtr0 vec
+      (spalette, _) = V.unsafeToForeignPtr0 p
+  B.createAndTrim (fromIntegral bsize) $ \dst -> do
+    withForeignPtr spalette $ \colors -> do
+      withForeignPtr sptr $ \src -> do
+        len <- c_img2palettized_sixel (castPtr dst) (castPtr src) (castPtr colors) (fromIntegral w) (fromIntegral h)
+        return (fromIntegral len)
 
 -- | Display sixel image via ByteString
 -- 
diff --git a/src/Data/Sixel/Internal.hs b/src/Data/Sixel/Internal.hs
--- a/src/Data/Sixel/Internal.hs
+++ b/src/Data/Sixel/Internal.hs
@@ -15,6 +15,7 @@
 foreign import ccall "bufsize" c_bufsize :: CInt -> CInt -> IO CInt
 
 foreign import ccall "img2sixel" c_img2sixel :: Ptr () -> Ptr () -> CInt -> CInt -> IO CInt
+foreign import ccall "img2palettized_sixel" c_img2palettized_sixel :: Ptr () -> Ptr () -> Ptr () -> CInt -> CInt -> IO CInt
 
 data LatexStr
   = LatexStr
@@ -50,7 +51,7 @@
   withSystemTempDirectory "sixel" $ \dir -> do
     writeFile (dir ++ "/sixel.tex") (latexStr str size)
     (_, outlog, errlog) <- readProcessWithExitCode "pdflatex" ["-output-directory=" ++ dir, dir ++ "/sixel.tex"] ""
-    readProcessWithExitCode "convert" [dir ++ "/sixel.pdf", "-quality", "90", dir ++ "/sixel.png"] ""
+    readProcessWithExitCode "gs" ["-dSAFER", "-r75", "-sDEVICE=png16m", "-o", dir ++ "/sixel.png", dir ++ "/sixel.pdf"] ""
     readImage (dir ++ "/sixel.png") >>= \case
       Left err -> return $ Left $ "can not read sixel.png. \n" ++ err ++ "\n" ++ errlog ++ "\n" ++ outlog
       Right img -> return $ Right img