diff --git a/toonz/sources/include/trasterfx.h b/toonz/sources/include/trasterfx.h
index 45795c8..8542bb0 100644
--- a/toonz/sources/include/trasterfx.h
+++ b/toonz/sources/include/trasterfx.h
@@ -146,6 +146,11 @@ public:
   bool m_applyShrinkToViewer;  //!< Whether shrink must be considered.   \note
                                //! Should be moved to TOutputProperties.
 
+  // when this flag is true, TLevelColumnFx::doGetBBox returns full image sized
+  // box instead of the bounding box. It takes effect only for Toonz Raster /
+  // Raster levels. Currently used only in Tile Fx Iwa. (see iwa_tilefx.cpp)
+  bool m_getFullSizeBBox;
+
   /*-- カメラサイズ --*/
   TRectD m_cameraBox;
   /*-- 途中でPreview計算がキャンセルされたときのフラグ --*/
diff --git a/toonz/sources/stdfx/iwa_tilefx.cpp b/toonz/sources/stdfx/iwa_tilefx.cpp
index 0ecd646..0fcdfb9 100644
--- a/toonz/sources/stdfx/iwa_tilefx.cpp
+++ b/toonz/sources/stdfx/iwa_tilefx.cpp
@@ -16,7 +16,7 @@ class Iwa_TileFx final : public TStandardRasterFx {
 
   enum tileQuantity { eNoTile = 1, eOneTile = 2, eMultipleTiles = 3 };
 
-  enum inputSize { eBoundingBox = 1, eCameraBox = 2 };
+  enum inputSize { eBoundingBox = 1, eCameraBox = 2, eImageSize = 3 };
 
   TIntEnumParamP m_inputSizeMode;
   TRasterFxPort m_input;
@@ -70,6 +70,7 @@ Iwa_TileFx::Iwa_TileFx()
 
   bindParam(this, "inputSize", m_inputSizeMode);
   m_inputSizeMode->addItem(eCameraBox, "Camera Box");
+  m_inputSizeMode->addItem(eImageSize, "Image Size");
 
   bindParam(this, "leftQuantity", m_leftQuantity);
   m_leftQuantity->addItem(eOneTile, "1 Tile");
@@ -182,7 +183,8 @@ void Iwa_TileFx::doCompute(TTile &tile, double frame,
   TRectD inputBox;
 
   int inputSizeMode =
-      m_inputSizeMode->getValue();  //	eBoundingBox = 1, eCameraBox = 2
+      m_inputSizeMode
+          ->getValue();  //	eBoundingBox = 1, eCameraBox = 2, eImageSize = 3
   if (inputSizeMode == eBoundingBox)
     m_input->getBBox(frame, inputBox, ri);
   else if (inputSizeMode == eCameraBox) {
@@ -191,6 +193,12 @@ void Iwa_TileFx::doCompute(TTile &tile, double frame,
     inputBox = TRectD(
         TPointD(ri.m_cameraBox.x0 + offset.x, ri.m_cameraBox.y0 + offset.y),
         TDimensionD(ri.m_cameraBox.getLx(), ri.m_cameraBox.getLy()));
+  } else if (inputSizeMode == eImageSize) {
+    TRenderSettings riAux(ri);
+    // set a tentative flag to obtain full image size. (see
+    // TLevelColumnFx::doGetBBox)
+    riAux.m_getFullSizeBBox = true;
+    m_input->getBBox(frame, inputBox, riAux);
   }
 
   double scale = sqrt(fabs(ri.m_affine.det()));
@@ -266,7 +274,7 @@ bool Iwa_TileFx::checkIfThisTileShouldBeComptedOrNot(int horizIndex,
 //------------------------------------------------------------------------------
 //! Make the tile of the image contained in \b inputTile in \b tile
 /*
-*/
+ */
 void Iwa_TileFx::makeTile(const TTile &inputTile, const TTile &tile) {
   tile.getRaster()->clear();
 
diff --git a/toonz/sources/tnzbase/trasterfx.cpp b/toonz/sources/tnzbase/trasterfx.cpp
index 12bd377..29f7ee5 100644
--- a/toonz/sources/tnzbase/trasterfx.cpp
+++ b/toonz/sources/tnzbase/trasterfx.cpp
@@ -183,7 +183,7 @@ inline std::string traduce(const TAffine &aff) {
       (areAlmostEqual(aff.a23, 0.0) ? "0" : ::to_string(aff.a23, 5));
 }
 
-}  // Local namespace
+}  // namespace
 
 //------------------------------------------------------------------------------
 
@@ -1073,7 +1073,8 @@ TRenderSettings::TRenderSettings()
     , m_isSwatch(false)
     , m_applyShrinkToViewer(false)
     , m_userCachable(true)
-    , m_isCanceled(NULL) {}
+    , m_isCanceled(NULL)
+    , m_getFullSizeBBox(false) {}
 
 //------------------------------------------------------------------------------
 
diff --git a/toonz/sources/toonzlib/tcolumnfx.cpp b/toonz/sources/toonzlib/tcolumnfx.cpp
index 800281b..8d58dad 100644
--- a/toonz/sources/toonzlib/tcolumnfx.cpp
+++ b/toonz/sources/toonzlib/tcolumnfx.cpp
@@ -1408,16 +1408,19 @@ bool TLevelColumnFx::doGetBBox(double frame, TRectD &bBox,
     TImageInfo imageInfo;
     getImageInfo(imageInfo, sl, cell.m_frameId);
 
-    TRect imageSavebox(imageInfo.m_x0, imageInfo.m_y0, imageInfo.m_x1,
-                       imageInfo.m_y1);
     double cx = 0.5 * imageInfo.m_lx;
     double cy = 0.5 * imageInfo.m_ly;
-    double x0 = (imageSavebox.x0 - cx);
-    double y0 = (imageSavebox.y0 - cy);
-    double x1 = x0 + imageSavebox.getLx();
-    double y1 = y0 + imageSavebox.getLy();
-    bBox      = TRectD(x0, y0, x1, y1);
-
+    if (info.m_getFullSizeBBox) {
+      bBox = TRectD(-cx, -cy, cx, cy);
+    } else {
+      TRect imageSavebox(imageInfo.m_x0, imageInfo.m_y0, imageInfo.m_x1,
+                         imageInfo.m_y1);
+      double x0 = (imageSavebox.x0 - cx);
+      double y0 = (imageSavebox.y0 - cy);
+      double x1 = x0 + imageSavebox.getLx();
+      double y1 = y0 + imageSavebox.getLy();
+      bBox      = TRectD(x0, y0, x1, y1);
+    }
     dpi = imageInfo.m_dpix / Stage::inch;
   } else {
     TImageP img = m_levelColumn->getCell(row).getImage(false);