diff --git a/iipsrv/src/BioFormatsImage.cc b/iipsrv/src/BioFormatsImage.cc
index 404e53c..45cb19a 100644
--- a/iipsrv/src/BioFormatsImage.cc
+++ b/iipsrv/src/BioFormatsImage.cc
@@ -17,6 +17,8 @@ void BioFormatsImage::openImage() throw(file_error)
 {
 
   string filename = getFileName(currentX, currentY);
+  logfile << "BioFormats :: openImage() :: filename: " << filename << endl
+          << flush;
 
   // get the file modification date/time.   return false if not changed, return true if change compared to the stored info.
   bool modified = updateTimestamp(filename);
diff --git a/iipsrv/src/OpenSlideImage.cc b/iipsrv/src/OpenSlideImage.cc
index 23fa017..aba6169 100644
--- a/iipsrv/src/OpenSlideImage.cc
+++ b/iipsrv/src/OpenSlideImage.cc
@@ -18,6 +18,8 @@ extern std::ofstream logfile;
 void OpenSlideImage::openImage() throw (file_error) {
 
   string filename = getFileName(currentX, currentY);
+  logfile << "Openslide :: openImage() :: filename: " << filename << endl
+          << flush;
 
   // get the file modification date/time.   return false if not changed, return true if change compared to the stored info.
   bool modified = updateTimestamp(filename);