diff -r 5dc02b23752f -r 3e2da88830cd src/gui/image/qpnghandler.cpp
--- a/src/gui/image/qpnghandler.cpp	Tue Jul 06 15:10:48 2010 +0300
+++ b/src/gui/image/qpnghandler.cpp	Wed Aug 18 10:37:55 2010 +0300
@@ -892,13 +892,15 @@
 
 bool QPngHandler::canRead() const
 {
-    if (d->state == QPngHandlerPrivate::Ready) {
-        if (!canRead(device()))
-            return false;
+    if (d->state == QPngHandlerPrivate::Ready && !canRead(device()))
+        return false;
+
+    if (d->state != QPngHandlerPrivate::Error) {
         setFormat("png");
         return true;
     }
-    return d->state != QPngHandlerPrivate::Error;
+
+    return false;
 }
 
 bool QPngHandler::canRead(QIODevice *device)