diff --git a/core/document.cpp b/core/document.cpp
index 33ff1182b..65bce3b1d 100644
--- a/core/document.cpp
+++ b/core/document.cpp
@@ -1366,6 +1366,9 @@ void DocumentPrivate::sendGeneratorPixmapRequest()
         }
         const long screenSize = screen->devicePixelRatio() * screen->size().width() * screen->devicePixelRatio() * screen->size().height();
 
+        // Make sure the page is the right size to receive the pixmap
+        r->page()->setPageSize(r->observer(), r->width(), r->height());
+
         // If it's a preload but the generator is not threaded no point in trying to preload
         if (r->preload() && !m_generator->hasFeature(Generator::Threaded)) {
             m_pixmapRequestsStack.pop_back();
diff --git a/core/page.cpp b/core/page.cpp
index 70f9c5463..00dde949c 100644
--- a/core/page.cpp
+++ b/core/page.cpp
@@ -221,11 +221,6 @@ bool Page::hasPixmap(DocumentObserver *observer, int width, int height, const No
     TilesManager *tm = d->tilesManager(observer);
     if (tm) {
         if (width != tm->width() || height != tm->height()) {
-            // FIXME hasPixmap should not be calling setSize on the TilesManager this is not very "const"
-            // as this function claims to be
-            if (width != -1 && height != -1) {
-                tm->setSize(width, height);
-            }
             return false;
         }
 
@@ -250,6 +245,14 @@ bool Page::hasPixmap(DocumentObserver *observer, int width, int height, const No
     return (pixmap->width() == width && pixmap->height() == height);
 }
 
+void Page::setPageSize(DocumentObserver *observer, int width, int height)
+{
+    TilesManager *tm = d->tilesManager(observer);
+    if (tm) {
+        tm->setSize(width, height);
+    }
+}
+
 bool Page::hasTextPage() const
 {
     return d->m_text != nullptr;
diff --git a/core/page.h b/core/page.h
index dd065073d..11bebd5da 100644
--- a/core/page.h
+++ b/core/page.h
@@ -141,6 +141,11 @@ public:
      */
     bool hasPixmap(DocumentObserver *observer, int width = -1, int height = -1, const NormalizedRect &rect = NormalizedRect()) const;
 
+    /**
+     * Sets the size of the page (in screen pixels) if there is a TilesManager.
+     */
+    void setPageSize(DocumentObserver *observer, int width, int height);
+
     /**
      * Returns whether the page provides a text page (@ref TextPage).
      */