diff --git a/src/main/java/lc/captchas/FontFunCaptcha.java b/src/main/java/lc/captchas/FontFunCaptcha.java
index 1007078..be09485 100644
--- a/src/main/java/lc/captchas/FontFunCaptcha.java
+++ b/src/main/java/lc/captchas/FontFunCaptcha.java
@@ -1,6 +1,5 @@
 package lc.captchas;
 
-import javax.imageio.ImageIO;
 import java.awt.*;
 import java.awt.image.BufferedImage;
 import java.io.ByteArrayOutputStream;
@@ -10,6 +9,7 @@ import java.util.Map;
 import java.util.List;
 import lc.captchas.interfaces.Challenge;
 import lc.captchas.interfaces.ChallengeProvider;
+import lc.misc.DPISetter;
 import lc.misc.HelperFunctions;
 
 public class FontFunCaptcha implements ChallengeProvider {
@@ -74,7 +74,8 @@ public class FontFunCaptcha implements ChallengeProvider {
     graphics2D.dispose();
     ByteArrayOutputStream baos = new ByteArrayOutputStream();
     try {
-      ImageIO.write(img, "png", baos);
+      DPISetter dpi = new DPISetter();
+      dpi.setDPI(baos, img);
     } catch (Exception e) {
       e.printStackTrace();
     }
diff --git a/src/main/java/lc/captchas/ShadowTextCaptcha.java b/src/main/java/lc/captchas/ShadowTextCaptcha.java
index b510b9a..16f2b54 100644
--- a/src/main/java/lc/captchas/ShadowTextCaptcha.java
+++ b/src/main/java/lc/captchas/ShadowTextCaptcha.java
@@ -1,6 +1,5 @@
 package lc.captchas;
 
-import javax.imageio.ImageIO;
 import java.awt.Graphics2D;
 import java.awt.RenderingHints;
 import java.awt.Color;
@@ -14,6 +13,7 @@ import java.util.Map;
 import java.util.List;
 
 import lc.misc.HelperFunctions;
+import lc.misc.DPISetter;
 import lc.captchas.interfaces.Challenge;
 import lc.captchas.interfaces.ChallengeProvider;
 
@@ -67,7 +67,8 @@ public class ShadowTextCaptcha implements ChallengeProvider {
     g2d.dispose();
     ByteArrayOutputStream baos = new ByteArrayOutputStream();
     try {
-      ImageIO.write(img2, "png", baos);
+      DPISetter dpi = new DPISetter();
+      dpi.setDPI(baos, img2);
     } catch (Exception e) {
       e.printStackTrace();
     }
diff --git a/src/main/scala/lc/captchas/DebugCaptcha.scala b/src/main/scala/lc/captchas/DebugCaptcha.scala
index 787b6cf..5a0f0f1 100644
--- a/src/main/scala/lc/captchas/DebugCaptcha.scala
+++ b/src/main/scala/lc/captchas/DebugCaptcha.scala
@@ -1,6 +1,5 @@
 package lc.captchas
 
-import javax.imageio.ImageIO
 import java.awt.Color
 import java.awt.Font
 import java.awt.font.TextLayout
@@ -12,6 +11,7 @@ import java.util.List
 import lc.misc.HelperFunctions
 import lc.captchas.interfaces.Challenge
 import lc.captchas.interfaces.ChallengeProvider
+import lc.misc.DPISetter
 
 /** This captcha is only for debugging purposes. It creates very simple captchas that are deliberately easy to solve with OCR engines */
 class DebugCaptcha extends ChallengeProvider {
@@ -53,7 +53,8 @@ class DebugCaptcha extends ChallengeProvider {
     graphics2D.dispose()
     val baos = new ByteArrayOutputStream()
     try {
-      ImageIO.write(img, "png", baos)
+      val dpi = new DPISetter();
+      dpi.setDPI(baos, img);
     } catch {
       case e: Exception =>
         e.printStackTrace()
diff --git a/src/main/scala/lc/captchas/LabelCaptcha.scala b/src/main/scala/lc/captchas/LabelCaptcha.scala
index cd008e7..7b85e06 100644
--- a/src/main/scala/lc/captchas/LabelCaptcha.scala
+++ b/src/main/scala/lc/captchas/LabelCaptcha.scala
@@ -10,6 +10,7 @@ import java.awt.Color
 import lc.captchas.interfaces.ChallengeProvider
 import lc.captchas.interfaces.Challenge
 import java.util.{List => JavaList, Map => JavaMap}
+import lc.misc.DPISetter
 
 class LabelCaptcha extends ChallengeProvider {
   private var knownFiles = new File("known").list.toList
@@ -49,7 +50,8 @@ class LabelCaptcha extends ChallengeProvider {
 
       val token = encrypt(knownImageFile + "," + unknownImageFile)
       val baos = new ByteArrayOutputStream()
-      ImageIO.write(mergedImage, "png", baos)
+      val dpi = new DPISetter();
+      dpi.setDPI(baos, mergedImage);
 
       new Challenge(baos.toByteArray(), "image/png", token)
     }