diff --git a/fileformats.c b/fileformats.c
index 2244b8e5..1ae2eec2 100644
--- a/fileformats.c
+++ b/fileformats.c
@@ -1672,8 +1672,7 @@ word GIF_get_next_code(void)
 
 void GIF_new_pixel(T_IO_Context * context, T_GIF_IDB *idb, byte color)
 {
-  if (color != context->Transparent_color) // transparent color
-    Set_pixel(context, idb->Pos_X+GIF_pos_X, idb->Pos_Y+GIF_pos_Y,color);
+  Set_pixel(context, idb->Pos_X+GIF_pos_X, idb->Pos_Y+GIF_pos_Y,color);
 
   GIF_pos_X++;
 
@@ -1855,9 +1854,17 @@ void Load_GIF(T_IO_Context * context)
                       && Read_byte(GIF_file,&(GCE.Transparent_color)))
                     {
                       if (GCE.Packed_fields & 1)
+                      {
+                        if (number_LID == 0)
+                          context->Background_transparent = 1;
                         context->Transparent_color= GCE.Transparent_color;
+                      }
                       else
-                        context->Transparent_color = -1;
+                      {
+                        if (number_LID == 0)
+                          context->Background_transparent = 0;
+                        context->Transparent_color = 0; // Reset transparent color
+                      }
                     
                     }
                     else
@@ -2170,7 +2177,7 @@ void Save_GIF(T_IO_Context * context)
         LSDB.Height=context->Height;
       }
       LSDB.Resol  =0x97;          // Image en 256 couleurs, avec une palette
-      LSDB.Backcol=0;
+      LSDB.Backcol=context->Transparent_color;
       LSDB.Aspect =0;             // Palette normale
 
       // On sauve le LSDB dans le fichier
@@ -2213,9 +2220,15 @@ void Save_GIF(T_IO_Context * context)
             current_layer++)
           {
             // Write a Graphic Control Extension
-            char GCE_block[] = "\x21\xF9\x04\x05\x05\x00\x00\x00";
-            //if (Main_current_layer > 0)
-            //  GCE_block[3] = '\x05';
+            char GCE_block[] = "\x21\xF9\x04\x04\x05\x00\x00\x00";
+            // 'Default' values:
+            //    Disposal method "Do not dispose"
+            //    Duration 5/100s (minimum viable value for current web browsers)
+            
+            if (current_layer > 0 || context->Background_transparent)
+              GCE_block[3] |= 1; // Transparent color flag
+            GCE_block[6] = context->Transparent_color;
+            
             Set_layer(context, current_layer);
             
             if (current_layer == context->Nb_layers -1)
@@ -3231,6 +3244,9 @@ void Load_PNG(T_IO_Context * context)
   char filename[MAX_PATH_CHARACTERS]; // Nom complet du fichier
   byte png_header[8];  
   byte row_pointers_allocated;
+  png_bytep trans;
+  int num_trans;
+  png_color_16p trans_values;
  
   png_structp png_ptr;
   png_infop info_ptr;
@@ -3388,11 +3404,24 @@ void Load_PNG(T_IO_Context * context)
                     free(palette);
                     palette = NULL;
                   }
-                  
                   if (color_type != PNG_COLOR_TYPE_RGB && color_type != PNG_COLOR_TYPE_RGB_ALPHA)
                   {
                     Palette_loaded(context);
                   }
+                  // Transparency (tRNS)
+                  if (png_get_tRNS(png_ptr, info_ptr, &trans, &num_trans, &trans_values))
+                  {
+                    int i;
+                    for (i=0; i<num_trans; i++)
+                    {
+                      if (trans[i]==0)
+                      {
+                        context->Transparent_color = i;
+                        context->Background_transparent = 1;
+                        break;
+                      }
+                    }
+                  }
                   
                   context->Width=info_ptr->width;
                   context->Height=info_ptr->height;
@@ -3546,6 +3575,17 @@ void Save_PNG(T_IO_Context * context)
             }
             png_set_text(png_ptr, info_ptr, text_ptr, nb_text_chunks);
           }
+          if (context->Background_transparent)
+          {
+            // Transparency
+            byte opacity[256];
+            // Need to fill a segment with '255', up to the transparent color
+            // which will have a 0. This piece of data (1 to 256 bytes)
+            // will be stored in the file.
+            memset(opacity, 255,context->Transparent_color);
+            opacity[context->Transparent_color]=0;
+            png_set_tRNS(png_ptr, info_ptr, opacity, (int)1 + context->Transparent_color,0);
+          }
           switch(Pixel_ratio)
           {
             case PIXEL_WIDE:
diff --git a/fonts/GrafX2_Classic.gif b/fonts/GrafX2_Black.gif
similarity index 82%
rename from fonts/GrafX2_Classic.gif
rename to fonts/GrafX2_Black.gif
index af4d73c3..221e3abb 100644
Binary files a/fonts/GrafX2_Classic.gif and b/fonts/GrafX2_Black.gif differ
diff --git a/fonts/GrafX2_Dark.gif b/fonts/GrafX2_Dark.gif
new file mode 100644
index 00000000..96e4982a
Binary files /dev/null and b/fonts/GrafX2_Dark.gif differ
diff --git a/layers.c b/layers.c
index 7253c0ee..1b3a27c0 100644
--- a/layers.c
+++ b/layers.c
@@ -25,6 +25,10 @@
 #include "windows.h"
 #include "engine.h"
 #include "pages.h"
+#include "sdlscreen.h"
+#include "input.h"
+#include "help.h"
+#include "misc.h"
 
 void Layer_activate(byte layer, short side)
 {
@@ -164,9 +168,93 @@ void Button_Layer_toggle(void)
   Layer_activate(layer, RIGHT_SIDE);
 }
 
+static void Draw_transparent_color(byte color)
+{
+  char buf[4];
+  Num2str(color, buf, 3);
+  Print_in_window(63,39,buf,MC_Black,MC_Light);
+  Window_rectangle(90,39,13,7,color);
+}
+
+static void Draw_transparent_background(byte background)
+{
+  Print_in_window(99,57,background?"X":" ",MC_Black,MC_Light);
+}
+
+
 void Button_Layer_menu(void)
 {
+  byte transparent_color = Main_backups->Pages->Transparent_color;
+  byte transparent_background = Main_backups->Pages->Background_transparent;
+  short clicked_button;
+  byte color;
+  byte click;
+
+  Open_window(122,100,"Layers");
+
+  Window_display_frame_in( 6, 21,110, 52);
+  Print_in_window(14,18,"Transparency",MC_Dark,MC_Light);
+
+  Print_in_window(11,38,"Color",MC_Black,MC_Light);
+  Window_set_normal_button(54, 36, 56,13,"" , 0,1,KEY_NONE); // 1
+  Draw_transparent_color(transparent_color);
+  
+  Print_in_window(11,57,"Background",MC_Black,MC_Light);
+  Window_set_normal_button(95, 54, 15,13,"" , 0,1,KEY_NONE); // 2
+  Draw_transparent_background(transparent_background);
+  
+  Window_set_normal_button( 7, 78, 51,14,"OK" , 0,1,SDLK_RETURN); // 3
+  Window_set_normal_button(63, 78, 51,14,"Cancel", 0,1,KEY_ESC); // 4
+  
+  Update_window_area(0,0,Window_width, Window_height);
+
+  do
+  {
+    
+    clicked_button=Window_clicked_button();
+    //if (Is_shortcut(Key,0x100+BUTTON_HELP))
+    //  Window_help(BUTTON_LAYERS, NULL);
+    switch(clicked_button)
+    {
+      case 1: // color
+        Get_color_behind_window(&color,&click);
+        if (click && transparent_color!=color)
+        {
+          transparent_color=color;
+          Hide_cursor();
+          Draw_transparent_color(transparent_color);
+          Display_cursor();
+          Wait_end_of_click();
+        }
+        break;
+        
+      case 2: // background
+        transparent_background = !transparent_background;
+        Hide_cursor();
+        Draw_transparent_background(transparent_background);
+        Display_cursor();
+        break;
+    }
+  }
+  while (clicked_button<3);
+
+  // On exit
   Hide_cursor();
+  Close_window();
+  if (clicked_button==3)
+  {
+    // Accept changes
+    if (Main_backups->Pages->Transparent_color != transparent_color ||
+        Main_backups->Pages->Background_transparent != transparent_background)
+    {
+      Backup_layers(-1);
+      Main_backups->Pages->Transparent_color = transparent_color;
+      Main_backups->Pages->Background_transparent = transparent_background;
+      Redraw_layered_image();
+      Display_all_screen();
+      End_of_modification();
+    }
+  }
   Unselect_button(BUTTON_LAYER_MENU);
   Display_cursor();
 }
diff --git a/loadsave.c b/loadsave.c
index 6d2e1e31..2ced475d 100644
--- a/loadsave.c
+++ b/loadsave.c
@@ -179,6 +179,11 @@ void Set_pixel(T_IO_Context *context, short x_pos, short y_pos, byte color)
       
     // Chargement des pixels dans la preview
     case CONTEXT_PREVIEW:
+      // Skip pixels of transparent index if :
+      // - It's the first layer, and image has transparent background.
+      // - or it's a layer above the first one
+      if (color == context->Transparent_color && (context->Current_layer > 0 || context->Background_transparent))
+        break;
       if (((x_pos % context->Preview_factor_X)==0) && ((y_pos % context->Preview_factor_Y)==0))
       {
         if (context->Ratio == PIXEL_WIDE && 
@@ -375,6 +380,8 @@ void Pre_load(T_IO_Context *context, short width, short height, long file_size,
   context->Height = height;
   context->Ratio = ratio;
   context->Nb_layers = 1;
+  context->Transparent_color=0;
+  context->Background_transparent=0;
   
   switch(context->Type)
   {
@@ -741,6 +748,10 @@ void Load_image(T_IO_Context *context)
         
         Main_current_layer = context->Nb_layers - 1;
         Main_layers_visible = (2<<Main_current_layer)-1;
+        
+        // Load the transparency data
+        Main_backups->Pages->Transparent_color = context->Transparent_color;
+        Main_backups->Pages->Background_transparent = context->Background_transparent;
   
         // Correction des dimensions
         if (Main_image_width<1)
@@ -1032,7 +1043,6 @@ void Init_context_preview(T_IO_Context * context, char *file_name, char *file_di
   context->File_name = file_name;
   context->File_directory = file_directory;
   context->Format = Main_fileformat; // FIXME ?
-  
 }
 
 /// Setup for loading/saving the current main image
@@ -1050,6 +1060,7 @@ void Init_context_layered_image(T_IO_Context * context, char *file_name, char *f
   context->Nb_layers = Main_backups->Pages->Nb_layers;
   strcpy(context->Comment, Main_comment);
   context->Transparent_color=Main_backups->Pages->Transparent_color;
+  context->Background_transparent=Main_backups->Pages->Background_transparent;
   if (Pixel_ratio == PIXEL_WIDE || Pixel_ratio == PIXEL_WIDE2)
     context->Ratio=PIXEL_WIDE;
   else if (Pixel_ratio == PIXEL_TALL || Pixel_ratio == PIXEL_TALL2)
@@ -1082,7 +1093,8 @@ void Init_context_brush(T_IO_Context * context, char *file_name, char *file_dire
   context->Height = Brush_height;
   context->Nb_layers = 1;
   // Solid save... could use BG color maybe
-  context->Transparent_color=-1;
+  context->Transparent_color=0;
+  context->Background_transparent=0;
   context->Ratio=PIXEL_SIMPLE;
   context->Target_address=Brush;
   context->Pitch=Brush_width;
@@ -1102,7 +1114,8 @@ void Init_context_surface(T_IO_Context * context, char *file_name, char *file_di
   // context->Width
   // context->Height
   context->Nb_layers = 1;
-  context->Transparent_color=-1;
+  context->Transparent_color=0;
+  context->Background_transparent=0;
   context->Ratio=PIXEL_SIMPLE;
   //context->Target_address
   //context->Pitch
@@ -1111,6 +1124,8 @@ void Init_context_surface(T_IO_Context * context, char *file_name, char *file_di
 /// Function to call when need to switch layers.
 void Set_layer(T_IO_Context *context, byte layer)
 {
+  context->Current_layer = layer;
+
   if (context->Type == CONTEXT_MAIN_IMAGE)
   {
     // This awful thing is the part that happens on load
diff --git a/loadsave.h b/loadsave.h
index ec488fd1..2e56cdc3 100644
--- a/loadsave.h
+++ b/loadsave.h
@@ -56,7 +56,8 @@ typedef struct
   short Height;
   byte Nb_layers;
   char Comment[COMMENT_SIZE+1];
-  short Transparent_color;
+  byte Background_transparent;
+  byte Transparent_color;
   /// Pixel ratio of the image
   enum PIXEL_RATIO Ratio;
   
@@ -64,7 +65,10 @@ typedef struct
   byte *Target_address;
   /// Pitch: Difference of addresses between one pixel and the one just "below" it
   long Pitch;
-  
+
+  /// Internal: during load, marks which layer is being loaded.
+  short Current_layer;
+
   /// Internal: Used to mark truecolor images on loading. Only used by preview.
   //byte Is_truecolor;
   /// Internal: Temporary RGB buffer when loading 24bit images
diff --git a/pages.c b/pages.c
index 0c5ae407..7ba40e6d 100644
--- a/pages.c
+++ b/pages.c
@@ -76,6 +76,7 @@ T_Page * New_page(byte nb_layers)
     page->File_format=DEFAULT_FILEFORMAT;
     page->Nb_layers=nb_layers;
     page->Transparent_color=0; // Default transparent color
+    page->Background_transparent=0;
     page->Next = page->Prev = NULL;
   }
   return page;
diff --git a/struct.h b/struct.h
index c16f1ce6..413f5458 100644
--- a/struct.h
+++ b/struct.h
@@ -347,7 +347,8 @@ typedef struct T_Page
   byte      File_format;                        ///< File format, in enum ::FILE_FORMATS
   struct T_Page *Next; ///< Pointer to the next backup
   struct T_Page *Prev; ///< Pointer to the previous backup
-  word      Transparent_color; ///< Index of transparent color. -1 or 0 to 255.
+  byte      Background_transparent; ///< Boolean, true if Layer 0 should have transparent pixels
+  byte      Transparent_color; ///< Index of transparent color. 0 to 255.
   byte      Nb_layers; ///< Number of layers
   byte *    Image[0];  ///< Pixel data for the (first layer of) image.
   // No field after Image[] ! Dynamic layer allocation for Image[1], [2] etc.