diff --git a/src/main/java/the/bytecode/club/bytecodeviewer/gui/resourceviewer/viewer/FileViewer.java b/src/main/java/the/bytecode/club/bytecodeviewer/gui/resourceviewer/viewer/FileViewer.java
index 1571232d..25e5d5df 100644
--- a/src/main/java/the/bytecode/club/bytecodeviewer/gui/resourceviewer/viewer/FileViewer.java
+++ b/src/main/java/the/bytecode/club/bytecodeviewer/gui/resourceviewer/viewer/FileViewer.java
@@ -73,13 +73,12 @@ public class FileViewer extends ResourceViewer
         final byte[] contents = resource.getResourceBytes();
         final String nameLowerCase = this.resource.name.toLowerCase();
         final String onlyName = FilenameUtils.getName(nameLowerCase);
-        final String contentsAsString = new String(contents);
         final boolean hexViewerOnly = BytecodeViewer.viewer.viewPane1.getSelectedDecompiler() == Decompiler.HEXCODE_VIEWER &&
                 BytecodeViewer.viewer.viewPane2.getSelectedDecompiler() == Decompiler.NONE &&
                 BytecodeViewer.viewer.viewPane3.getSelectedDecompiler() == Decompiler.NONE;
         
         //image viewer
-        if (!MiscUtils.isPureAscii(contentsAsString) || hexViewerOnly)
+        if (MiscUtils.guessIfBinary(contents) || hexViewerOnly)
         {
             //TODO:
             //  + Add file header checks
@@ -144,7 +143,7 @@ public class FileViewer extends ResourceViewer
         
         textArea.setCodeFoldingEnabled(true);
         SyntaxLanguage.setLanguage(textArea, nameLowerCase);
-        textArea.setText(contentsAsString);
+        textArea.setText(new String(contents));
         textArea.setFont(new Font(Font.MONOSPACED, Font.PLAIN, (int) BytecodeViewer.viewer.fontSpinner.getValue()));
         textArea.setCaretPosition(0);
         
diff --git a/src/main/java/the/bytecode/club/bytecodeviewer/util/MiscUtils.java b/src/main/java/the/bytecode/club/bytecodeviewer/util/MiscUtils.java
index f586702c..71011aaa 100644
--- a/src/main/java/the/bytecode/club/bytecodeviewer/util/MiscUtils.java
+++ b/src/main/java/the/bytecode/club/bytecodeviewer/util/MiscUtils.java
@@ -54,7 +54,6 @@ import static the.bytecode.club.bytecodeviewer.BytecodeViewer.gson;
 
 public class MiscUtils
 {
-    private static final CharsetEncoder asciiEncoder = StandardCharsets.US_ASCII.newEncoder(); // or "ISO-8859-1" for ISO Latin 1
     private static final String AB = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
     private static final String AN = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
     private static final Random rnd = new Random();
@@ -247,9 +246,19 @@ public class MiscUtils
         while(list.size() > maxLength)
             list.remove(list.size() - 1);
     }
-    
-    public static boolean isPureAscii(String v) {
-        return asciiEncoder.canEncode(v);
+
+    /**
+     * Returns whether the bytes most likely represent binary data.
+     * Based on https://stackoverflow.com/a/13533390/5894824
+     */
+    public static boolean guessIfBinary(byte[] data) {
+        double ascii = 0;
+        double other = 0;
+        for (byte b : data) {
+            if (b == 0x09 || b == 0x0A || b == 0x0C || b == 0x0D || (b >= 0x20 && b <= 0x7E)) ascii++;
+            else other++;
+        }
+        return other != 0 && other / (ascii + other) > 0.25;
     }
     
     public static Language guessLanguage()