4 files changed, 35 insertions, 16 deletions
diff --git a/src/gui/image/qimage.cpp b/src/gui/image/qimage.cpp
index 234742e6b9..0916826529 100644
--- a/src/gui/image/qimage.cpp
+++ b/src/gui/image/qimage.cpp
@@ -2324,7 +2324,7 @@ static bool convert_RGB_to_RGB16_inplace(QImageData *data, Qt::ImageConversionFl
 static void convert_ARGB_PM_to_ARGB(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
 {
     Q_ASSERT(src->format == QImage::Format_ARGB32_Premultiplied || src->format == QImage::Format_RGBA8888_Premultiplied);
-    Q_ASSERT(dest->format == QImage::Format_ARGB32 || src->format == QImage::Format_RGBA8888);
+    Q_ASSERT(dest->format == QImage::Format_ARGB32 || dest->format == QImage::Format_RGBA8888);
     Q_ASSERT(src->width == dest->width);
     Q_ASSERT(src->height == dest->height);
 
@@ -3853,6 +3853,9 @@ static InPlace_Image_Converter inplace_converter_map[QImage::NImageFormats][QIma
         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
     }, // Format_RGB444
     {
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+    }, // Format_ARGB4444_Premultiplied
+    {
         0,
         0,
         0,
@@ -3989,7 +3992,7 @@ void qGamma_correct_back_to_linear_cs(QImage *image)
     The specified image conversion \a flags control how the image data
     is handled during the conversion process.
 
-    \sa {QImage#Image Format}{Image Format}
+    \sa {Image Formats}
 */
 QImage QImage::convertToFormat(Format format, Qt::ImageConversionFlags flags) const
 {
diff --git a/src/gui/image/qimageiohandler.cpp b/src/gui/image/qimageiohandler.cpp
index 04e3213c53..d67b22c31e 100644
--- a/src/gui/image/qimageiohandler.cpp
+++ b/src/gui/image/qimageiohandler.cpp
@@ -187,11 +187,15 @@
     return this handler.
 
     The json metadata file for the plugin needs to contain information
-    about the image formats the plugins supports. For a jpeg plugin, this
-    could e.g. look as follows:
+    about the image formats the plugins supports, together with the
+    corresponding MIME types (one for each format). For a jpeg plugin, this
+    could, for example, look as follows:
 
     \code
-    { "Keys": [ "jpg", "jpeg" ] }
+    {
+      "Keys": [ "jpg", "jpeg" ],
+      "MimeTypes": [ "image/jpeg", "image/jpeg" ]
+    }
     \endcode
 
     Different plugins can support different capabilities. For example,
@@ -537,23 +541,33 @@ QImageIOPlugin::~QImageIOPlugin()
 
 /*! \fn QImageIOPlugin::capabilities(QIODevice *device, const QByteArray &format) const
 
-    Returns the capabilities on the plugin, based on the data in \a
-    device and the format \a format. For example, if the
-    QImageIOHandler supports the BMP format, and the data in the
-    device starts with the characters "BM", this function should
-    return \l CanRead. If \a format is "bmp" and the handler supports
-    both reading and writing, this function should return \l CanRead |
-    \l CanWrite.
+    Returns the capabilities of the plugin, based on the data in \a
+    device and the format \a format.  If \a device is \c 0, it should
+    simply report whether the format can be read or written.  Otherwise,
+    it should attempt to determine whether the given format (or any
+    format supported by the plugin if \a format is empty) can be read
+    from or written to \a device.  It should do this without changing
+    the state of \a device (typically by using QIODevice::peek()).
+
+    For example, if the QImageIOPlugin supports the BMP format, \a format
+    is either empty or \c "bmp", and the data in the device starts with the
+    characters \c "BM", this function should return \l CanRead. If \a format
+    is \c "bmp", \a device is \c 0 and the handler supports both reading and
+    writing, this function should return \l CanRead | \l CanWrite.
+
+    Format names are always given in lower case.
 */
 
 /*!
     \fn QImageIOHandler *QImageIOPlugin::create(QIODevice *device, const QByteArray &format) const
 
     Creates and returns a QImageIOHandler subclass, with \a device
-    and \a format set. The \a format must come from the list returned by keys().
-    Format names are case sensitive.
+    and \a format set. The \a format must come from the values listed
+    in the \c "Keys" entry in the plugin metadata, or be empty.  If it is
+    empty, the data in \a device must have been recognized by the
+    capabilities() method (with a likewise empty format).
 
-    \sa keys()
+    Format names are always given in lower case.
 */
 
 #endif // QT_NO_IMAGEFORMATPLUGIN
diff --git a/src/gui/image/qimagewriter.cpp b/src/gui/image/qimagewriter.cpp
index e4065724be..900093b51b 100644
--- a/src/gui/image/qimagewriter.cpp
+++ b/src/gui/image/qimagewriter.cpp
@@ -772,7 +772,9 @@ QList<QByteArray> QImageWriter::supportedImageFormats()
 QList<QByteArray> QImageWriter::supportedMimeTypes()
 {
     QSet<QByteArray> mimeTypes;
+#ifndef QT_NO_IMAGEFORMAT_BMP
     mimeTypes << "image/bmp";
+#endif
 #ifndef QT_NO_IMAGEFORMAT_PPM
     mimeTypes << "image/x-portable-bitmap";
     mimeTypes << "image/x-portable-graymap";
diff --git a/src/gui/image/qpixmap.cpp b/src/gui/image/qpixmap.cpp
index 5f51358eb2..a620d34553 100644
--- a/src/gui/image/qpixmap.cpp
+++ b/src/gui/image/qpixmap.cpp
@@ -73,7 +73,7 @@ QT_BEGIN_NAMESPACE
 static bool qt_pixmap_thread_test()
 {
     if (!QCoreApplication::instance()) {
-        qFatal("QPixmap: Must construct a QApplication before a QPaintDevice");
+        qFatal("QPixmap: Must construct a QGuiApplication before a QPixmap");
         return false;
     }