diff --git a/rtgui/thumbnail.cc b/rtgui/thumbnail.cc
index 324a0c0c1..cc8e9ad81 100644
--- a/rtgui/thumbnail.cc
+++ b/rtgui/thumbnail.cc
@@ -194,7 +194,7 @@ void Thumbnail::_generateThumbnailImage ()
     }
 }
 
-bool Thumbnail::isSupported ()
+bool Thumbnail::isSupported () const
 {
     return cfs.supported;
 }
@@ -655,7 +655,7 @@ void Thumbnail::getFinalSize (const rtengine::procparams::ProcParams& pparams, i
     }
 }
 
-void Thumbnail::getOriginalSize (int& w, int& h)
+void Thumbnail::getOriginalSize (int& w, int& h) const
 {
     w = tw;
     h = th;
@@ -784,7 +784,7 @@ void Thumbnail::getAutoWB (double& temp, double& green, double equal, double tem
 }
 
 
-ThFileType Thumbnail::getType ()
+ThFileType Thumbnail::getType () const
 {
 
     return (ThFileType) cfs.format;
@@ -909,20 +909,6 @@ void Thumbnail::_loadThumbnail(bool firstTrial)
     }
 }
 
-/*
- * Read all thumbnail's data from the cache; build and save them if doesn't exist - MUTEX PROTECTED
- * This includes:
- *  - image's bitmap (*.rtti)
- *  - auto exposure's histogram (full thumbnail only)
- *  - embedded profile (full thumbnail only)
- *  - LiveThumbData section of the data file
- */
-void Thumbnail::loadThumbnail (bool firstTrial)
-{
-    MyMutex::MyLock lock(mutex);
-    _loadThumbnail(firstTrial);
-}
-
 /*
  * Save thumbnail's data to the cache - NON PROTECTED
  * This includes:
@@ -1178,7 +1164,7 @@ void Thumbnail::applyAutoExp (rtengine::procparams::ProcParams& pparams)
     }
 }
 
-const CacheImageData* Thumbnail::getCacheImageData()
+const CacheImageData* Thumbnail::getCacheImageData() const
 {
     return &cfs;
 }
diff --git a/rtgui/thumbnail.h b/rtgui/thumbnail.h
index aee5ee0a6..cda69f030 100644
--- a/rtgui/thumbnail.h
+++ b/rtgui/thumbnail.h
@@ -83,7 +83,6 @@ class Thumbnail
     void            _saveThumbnail ();
     void            _generateThumbnailImage ();
     int             infoFromImage (const Glib::ustring& fname, std::unique_ptr<rtengine::RawMetaDataLocation> rml = nullptr);
-    void            loadThumbnail (bool firstTrial = true);
     void            generateExifDateTimeStrings ();
 
     Glib::ustring    getCacheFileName (const Glib::ustring& subdir, const Glib::ustring& fext) const;
@@ -121,7 +120,7 @@ public:
     rtengine::IImage8* upgradeThumbImage    (const rtengine::procparams::ProcParams& pparams, int h, double& scale);
     void            getThumbnailSize        (int &w, int &h, const rtengine::procparams::ProcParams *pparams = nullptr);
     void            getFinalSize            (const rtengine::procparams::ProcParams& pparams, int& w, int& h);
-    void            getOriginalSize         (int& w, int& h);
+    void            getOriginalSize         (int& w, int& h) const;
 
     const Glib::ustring&  getExifString () const;
     const Glib::ustring&  getDateTimeString () const;
@@ -130,16 +129,16 @@ public:
     void                  getSpotWB (int x, int y, int rect, double& temp, double& green);
     void                  applyAutoExp (rtengine::procparams::ProcParams& pparams);
 
-    ThFileType      getType ();
+    ThFileType      getType () const;
     Glib::ustring   getFileName () const
     {
         return fname;
     }
     void            setFileName (const Glib::ustring &fn);
 
-    bool            isSupported ();
+    bool            isSupported () const;
 
-    const CacheImageData* getCacheImageData();
+    const CacheImageData* getCacheImageData() const;
     std::string     getMD5   () const;
 
     int             getRank  () const;