Pixmap updating QLabel

[Matt]

I am new to Qt as of yesterday, and I was hoping someone would be able to help me with a problem. I am writing a program to act like XKCD, but I can't get pixmap to update label. Here is a section, I will attach the full files in case they would help.

int val = 1;
XKCD::XKCD(QWidget *parent)
    : QWidget(parent)
{
  QString number;
  QString png = ".png";
  QString pics = "pics/";
  number.setNum(val);
  number.prepend(pics);
  number.append(png);
 
  QPixmap *original=new QPixmap(QString(number));
  QPixmap image(original->scaled ( 1300,700, Qt::KeepAspectRatio, Qt::SmoothTransformation ));
  QLabel *label = new QLabel(this);
  label->setPixmap(image);
  int pixwidth = image.width();
  int labelwidth = (WIDTH - pixwidth) / 2;
  label->setGeometry(labelwidth, SIZEY, pixwidth, 700);
}
 
void XKCD::OnPrev()
{
  val--;
  if (val < 1) {val = 0;}
  QString number;
  QString png = ".png";
  QString pics = "pics/";
  number = number.setNum(val);
  number = number.prepend(pics);
  number = number.append(png);
  QPixmap *original=new QPixmap(QString(number));
  QPixmap image= (original->scaled ( 1300, 600, Qt::KeepAspectRatio, Qt::SmoothTransformation ));
  QLabel *label = new QLabel(this);
  label->setPixmap(image);
  int pixwidth = image.width();
  int labelwidth = (WIDTH - pixwidth) / 2;
  label->setGeometry(labelwidth, SIZEY, pixwidth, 700);
  /* Debugging purposes */ std::cout << "Val is now: "<< val << ".  The image path is now: " << number.toStdString() << "." << std::endl;
}

int val = 1;
XKCD::XKCD(QWidget *parent)
    : QWidget(parent)
{
  QString number;
  QString png = ".png";
  QString pics = "pics/";
  number.setNum(val);
  number.prepend(pics);
  number.append(png);

  QPixmap *original=new QPixmap(QString(number));
  QPixmap image(original->scaled ( 1300,700, Qt::KeepAspectRatio, Qt::SmoothTransformation ));
  QLabel *label = new QLabel(this);
  label->setPixmap(image);
  int pixwidth = image.width();
  int labelwidth = (WIDTH - pixwidth) / 2;
  label->setGeometry(labelwidth, SIZEY, pixwidth, 700);
}

void XKCD::OnPrev()
{
  val--;
  if (val < 1) {val = 0;}
  QString number;
  QString png = ".png";
  QString pics = "pics/";
  number = number.setNum(val);
  number = number.prepend(pics);
  number = number.append(png);
  QPixmap *original=new QPixmap(QString(number));
  QPixmap image= (original->scaled ( 1300, 600, Qt::KeepAspectRatio, Qt::SmoothTransformation ));
  QLabel *label = new QLabel(this);
  label->setPixmap(image);
  int pixwidth = image.width();
  int labelwidth = (WIDTH - pixwidth) / 2;
  label->setGeometry(labelwidth, SIZEY, pixwidth, 700);
  /* Debugging purposes */ std::cout << "Val is now: "<< val << ".  The image path is now: " << number.toStdString() << "." << std::endl;
}

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Hopefully someone can help me, I haven't found anything in documentation yet. Thanks for looking at my problem.

Attached are my project files.
xkcd.cpp
xkcd.h
main.cpp

Edit: If it would be possible or easier to do using QImage, I am certainly open to that if someone could help me with it. My attempt to switch from QPixmap to QImage gave me a mile long set of errors that I couldn't find a workaround for.