diff --git a/src/pdf_jam.cpp b/src/pdf_jam.cpp
index 236a734..44a62bd 100644
--- a/src/pdf_jam.cpp
+++ b/src/pdf_jam.cpp
@@ -8,17 +8,57 @@ PDFJam::PDFJam(void) {
   
 }
 
-void PDFJam::run(void) {
-#if 0
-  if((pid = fork()) < 0) {
-    
-  }
-  else if(pid > 0) {
-    /* Parent. */
-  } else {
-    /* Child. */
-    system("echo 'tata' > /tmp/test.txt");
-  }
-#endif
+/* Ensure the folder exists. */
+void PDFJam::makeFolder(QString path) {
+  QString tmp = "mkdir -p %1";
+  int value = system(tmp.arg(path).toStdString().c_str());
+  if(value != 0)
+    qDebug() << "ERROR: Failed to make " << path;
+}
+
+void PDFJam::pushCommand(QString cmd) {
+  mutex.lock();
+  cmdQueue.push_back(cmd);
+  mutex.unlock();
+  if(!isRunning()) start();
+}
+
+void PDFJam::loadFile(QString fileName, int fileNum, int numPages) {
+  QString path = "/tmp/hpdf/%1/";
+  path = path.arg(QString::number(fileNum));
+  makeFolder(path);
+
+  QString tmp = "pdfjam %1 %2 -- outfile %3%4.pdf";
+  QString cmd = "";
+  for(int i = 1; i <= numPages; i++) {
+    cmd += tmp.arg(fileName).arg(QString::number(i)).arg(path).arg(QString::number(i)) + ";";
+  }
+  pushCommand(cmd);
+}
+
+QString PDFJam::nextCommand(void) {
+  QString cmd;
+  mutex.lock();
+  cmd = cmdQueue.first();
+  cmdQueue.pop_front();
+  mutex.unlock();
+  return cmd;
+}
+
+bool PDFJam::isQueueEmpty(void) {
+  return (cmdQueue.size()==0);
+}
+
+void PDFJam::run(void) {
+  while(!isQueueEmpty()) {
+    QString cmd = nextCommand();
+    int value = system(cmd.toStdString().c_str());
+    if(value != 0)
+      qDebug() << "ERROR: Failed to execute " << cmd;
+    else
+      qDebug() << "SUCCESS: executed " << cmd;
+  }
+
+  /*system("echo 'tata' > /tmp/test.txt");*/
 }
 
diff --git a/src/pdf_jam.h b/src/pdf_jam.h
index 548f9fd..14b8252 100644
--- a/src/pdf_jam.h
+++ b/src/pdf_jam.h
@@ -1,14 +1,28 @@
 #pragma once
+#include <QThread>
+#include <QMutex>
+#include <poppler-qt5.h>
+#include <QImage>
 
-class PDFJam { /*:public QThread {*/
+class PDFPageWidget;
+class QImage;
+
+class PDFJam : public QThread {
+  Q_OBJECT
 public:
   PDFJam(void);
 
+  void pushCommand(QString);
+  void loadFile(QString fileName, int, int);
+  void makeFolder(QString);
+
 protected:
   void run(void);
 
 private:
-  volatile bool stopped;
-
+  QVector<QString> cmdQueue;
+  QString nextCommand();
+  bool isQueueEmpty();
+  QMutex mutex;
 };
 
diff --git a/src/pdf_preview_widget.cpp b/src/pdf_preview_widget.cpp
index 5d8b1d7..b75fd32 100644
--- a/src/pdf_preview_widget.cpp
+++ b/src/pdf_preview_widget.cpp
@@ -12,21 +12,20 @@ void PDFPreviewWidget::setImage(QImage image) {
 }
 
 void PDFPreviewWidget::regenImage(void) {
-  if(pPage != NULL) {
-    double dpi;
-    double dpi2;
-    QSize targetSize  = this->size();
-    QSizeF oriSize    = pPage->pageSizeF();
-    double oriDpi     = 72;
-    dpi   = targetSize.height() / (float)oriSize.height()*72;
-    dpi2  = targetSize.width()  / (float)oriSize.width()*72;
-    dpi   = dpi<dpi2?dpi:dpi2;
-    previewImage = pPage->renderToImage(dpi, dpi);
-  }
+  double dpi;
+  double dpi2;
+  QSize targetSize  = this->size();
+  QSizeF oriSize    = pPage->pageSizeF();
+  double oriDpi     = 72;
+  dpi   = targetSize.height() / (float)oriSize.height()*72;
+  dpi2  = targetSize.width()  / (float)oriSize.width()*72;
+  dpi   = dpi<dpi2?dpi:dpi2;
+  previewImage = pPage->renderToImage(dpi, dpi);
 }
 
 void PDFPreviewWidget::previewUpdate(Poppler::Page* pp) {
   pPage = pp;
+  qDebug() << "Set new popler page" << pp;
   regenImage();
   update();
 }
@@ -36,7 +35,8 @@ void PDFPreviewWidget::pageClicked(QMouseEvent* mouseEvent, QImage image) {
 }
 
 void PDFPreviewWidget::resizeEvent(QResizeEvent* event) {
-  regenImage();
+  if(pPage != NULL)
+    regenImage();
 }
 
 void PDFPreviewWidget::paintEvent(QPaintEvent* event) {
diff --git a/src/pdf_table_widget.cpp b/src/pdf_table_widget.cpp
index b8d349b..e3e48ed 100644
--- a/src/pdf_table_widget.cpp
+++ b/src/pdf_table_widget.cpp
@@ -39,6 +39,7 @@ void PDFTableWidget::loadFile(QString fileName) {
   PDFFileWidget* fileWidget = new PDFFileWidget();
   fileWidget->setAncestor(this);
   fileWidget->setDocument(doc, fileName);
+  pdfJam.loadFile(fileName, files.size()-1, doc->numPages());
   connect(fileWidget, SIGNAL(pageClicked(QMouseEvent*,QImage)), this,
           SIGNAL(pageClicked(QMouseEvent*,QImage)));
   connect(fileWidget, SIGNAL(previewUpdate(Poppler::Page*)), this,
diff --git a/src/pdf_table_widget.h b/src/pdf_table_widget.h
index fd254ea..185e743 100644
--- a/src/pdf_table_widget.h
+++ b/src/pdf_table_widget.h
@@ -1,6 +1,7 @@
 #pragma once
 #include <QFrame>
 #include <poppler-qt5.h>
+#include "pdf_jam.h"
 
 class QImage;
 class QVBoxLayout;
@@ -16,6 +17,7 @@ public:
   void loadFile(QString fileName);
 
 protected:
+  PDFJam pdfJam;
   
 private:
   QVBoxLayout*  outerLayout;