diff --git a/source/net/yacy/cora/util/Html2Image.java b/source/net/yacy/cora/util/Html2Image.java
index 8e437a2fb..10bea0e2b 100644
--- a/source/net/yacy/cora/util/Html2Image.java
+++ b/source/net/yacy/cora/util/Html2Image.java
@@ -370,7 +370,15 @@ public class Html2Image {
             // i.e. convert -density 300 -trim yacy.pdf[0] -trim -resize 1024x -crop x1024+0+0 -quality 75% yacy-convert-300.jpg
             // note: both -trim are necessary, otherwise it is trimmed only on one side. The [0] selects the first page of the pdf
             final String command = convertCmd + " -alpha remove -density " + density + " -trim " + pdf.getAbsolutePath() + "[0] -trim -resize " + width + "x -crop x" + height + "+0+0 -quality " + quality + "% " + image.getAbsolutePath();
-            List<String> message = OS.execSynchronous(command);
+            List<String> message = OS.execSynchronous(new String[] {
+                    convertCmd,
+                    "-alpha", "remove", "-density", Integer.toString(density),
+                    "-trim", pdf.getAbsolutePath() + "[0]", "-trim",
+                    "-resize" + Integer.toString(width) + "x",
+                    "-crop x" + Integer.toString(height) + "+0+0",
+                    "-quality", Integer.toString(quality) + "%",
+                    image.getAbsolutePath()
+            });
             if (image.exists()) return true;
             ConcurrentLog.warn("Html2Image", "failed to create image with command: " + command);
             for (final String m: message) ConcurrentLog.warn("Html2Image", ">> " + m);
diff --git a/source/net/yacy/kelondro/logging/ThreadDump.java b/source/net/yacy/kelondro/logging/ThreadDump.java
index 6233e0b21..a4d842d02 100644
--- a/source/net/yacy/kelondro/logging/ThreadDump.java
+++ b/source/net/yacy/kelondro/logging/ThreadDump.java
@@ -137,7 +137,7 @@ public class ThreadDump extends HashMap<ThreadDump.StackTrace, List<String>> imp
             final int pid = OS.getPID();
 
             // call kill -3 (SIGQUIT) on the pid to request a core dump from the current process
-            if (pid >= 0) try {OS.execSynchronous("kill -3 " + pid);} catch (final IOException e) {}
+            if (pid >= 0) try {OS.execSynchronous(new String[]{"kill", "-3", Integer.toString(pid)});} catch (final IOException e) {}
         }
 
         // read the log from the dump
diff --git a/source/net/yacy/kelondro/util/OS.java b/source/net/yacy/kelondro/util/OS.java
index abf7d1695..7ca735e45 100644
--- a/source/net/yacy/kelondro/util/OS.java
+++ b/source/net/yacy/kelondro/util/OS.java
@@ -118,7 +118,6 @@ public final class OS {
         return s;
     }
 
-    @SuppressWarnings("deprecation")
     public static void deployScript(final File scriptFile, final String theScript) throws IOException {
         FileUtils.copy(UTF8.getBytes(theScript), scriptFile);
         if(!isWindows){ // set executable
@@ -141,7 +140,6 @@ public final class OS {
         return p >= 0 ? NumberTools.parseIntDecSubstring(pids, 0, p) : -1;
     }
 
-    @SuppressWarnings("deprecation")
     public static void execAsynchronous(final File scriptFile) throws IOException {
         // runs a script as separate thread
         String starterFileExtension = null;
@@ -164,15 +162,6 @@ public final class OS {
         FileUtils.deletedelete(starterFile);
     }
 
-    @SuppressWarnings("deprecation")
-    public static List<String> execSynchronous(final String command) throws IOException {
-        // runs a unix/linux command and returns output as Vector of Strings
-        // this method blocks until the command is executed
-        final Process p = Runtime.getRuntime().exec(command);
-        return readStreams(p);
-    }
-
-    @SuppressWarnings("deprecation")
     public static List<String> execSynchronous(final String[] command) throws IOException {
         // runs a unix/linux command and returns output as Vector of Strings
         // this method blocks until the command is executed
@@ -212,14 +201,15 @@ public final class OS {
 
     public static void main(final String[] args) {
         try {
-            final List<String> v = execSynchronous("/usr/local/bin/wkhtmltoimage");
+            final List<String> v = execSynchronous(new String[]{"/usr/local/bin/wkhtmltoimage"});
             for (final String r: v) java.lang.System.out.println(r);
         } catch (final IOException e) {
+            e.printStackTrace();
         }
         /*
-		if (args[0].equals("-m")) {
-			java.lang.System.out.println("Maximum possible memory: " + Integer.toString(getWin32MaxHeap()) + "m");
-		}
+        if (args[0].equals("-m")) {
+            java.lang.System.out.println("Maximum possible memory: " + Integer.toString(getWin32MaxHeap()) + "m");
+        }
          */
     }