Properly copy images for the XML output.

Use the exact same mechanism that is used for the HTML/LaTeX/... output,
which is findAndCopyImage() in docparser.cpp, because that one works,
unlike the method here. Not sure why that function doesn't handle XML as
well. Also not sure how to integrate this into the automated tests.

src/xmldocvisitor.cpp

@@ -770,17 +770,22 @@ void XmlDocVisitor::visitPre(DocImage *img)
   visitPreStart(m_t, "image", FALSE, this, img->children(), baseName, TRUE, img->type(), img->width(), img->height());
 
   // copy the image to the output dir
-  QFile inImage(img->name());
-  QFile outImage(Config_getString(XML_OUTPUT)+"/"+baseName.data());
-  if (inImage.open(IO_ReadOnly))
+  FileDef *fd;
+  bool ambig;
+  if ((fd=findFileDef(Doxygen::imageNameDict,img->name(),ambig)))
   {
-    if (outImage.open(IO_WriteOnly))
+    QFile inImage(fd->absFilePath());
+    QFile outImage(Config_getString(XML_OUTPUT)+"/"+baseName.data());
+    if (inImage.open(IO_ReadOnly))
     {
-      char *buffer = new char[inImage.size()];
-      inImage.readBlock(buffer,inImage.size());
-      outImage.writeBlock(buffer,inImage.size());
-      outImage.flush();
-      delete[] buffer;
+      if (outImage.open(IO_WriteOnly))
+      {
+        char *buffer = new char[inImage.size()];
+        inImage.readBlock(buffer,inImage.size());
+        outImage.writeBlock(buffer,inImage.size());
+        outImage.flush();
+        delete[] buffer;
+      }
     }
   }
 }