diff --git a/core/fpdfapi/page/cpdf_dib.cpp b/core/fpdfapi/page/cpdf_dib.cpp
index 95a09f8..c87e196 100644
--- a/core/fpdfapi/page/cpdf_dib.cpp
+++ b/core/fpdfapi/page/cpdf_dib.cpp
@@ -1196,6 +1196,10 @@
   return m_pDecoder && m_pDecoder->SkipToScanline(line, pPause);
 }
 
+uint32_t CPDF_DIB::GetEstimatedImageMemoryBurden() const {
+  return m_pCachedBitmap ? m_pCachedBitmap->GetEstimatedImageMemoryBurden() : 0;
+}
+
 bool CPDF_DIB::TransMask() const {
   return m_bLoadMask && m_GroupFamily == CPDF_ColorSpace::Family::kDeviceCMYK &&
          m_Family == CPDF_ColorSpace::Family::kDeviceCMYK;
diff --git a/core/fpdfapi/page/cpdf_dib.h b/core/fpdfapi/page/cpdf_dib.h
index a13d571..ae9e8c3 100644
--- a/core/fpdfapi/page/cpdf_dib.h
+++ b/core/fpdfapi/page/cpdf_dib.h
@@ -45,9 +45,10 @@
   bool Load(CPDF_Document* pDoc, const CPDF_Stream* pStream);
 
   // CFX_DIBBase:
-  bool SkipToScanline(int line, PauseIndicatorIface* pPause) const override;
   uint8_t* GetBuffer() const override;
   pdfium::span<const uint8_t> GetScanline(int line) const override;
+  bool SkipToScanline(int line, PauseIndicatorIface* pPause) const override;
+  uint32_t GetEstimatedImageMemoryBurden() const override;
 
   RetainPtr<CPDF_ColorSpace> GetColorSpace() const { return m_pColorSpace; }
   uint32_t GetMatteColor() const { return m_MatteColor; }
diff --git a/core/fpdfapi/render/cpdf_imagecacheentry.cpp b/core/fpdfapi/render/cpdf_imagecacheentry.cpp
index b170f29..840505c 100644
--- a/core/fpdfapi/render/cpdf_imagecacheentry.cpp
+++ b/core/fpdfapi/render/cpdf_imagecacheentry.cpp
@@ -18,22 +18,6 @@
 #include "core/fpdfapi/render/cpdf_rendercontext.h"
 #include "core/fpdfapi/render/cpdf_renderstatus.h"
 #include "core/fxge/dib/cfx_dibitmap.h"
-#include "third_party/base/check.h"
-#include "third_party/base/numerics/safe_conversions.h"
-
-namespace {
-
-uint32_t GetEstimatedImageSize(const RetainPtr<CFX_DIBBase>& pDIB) {
-  if (!pDIB || !pDIB->GetBuffer())
-    return 0;
-
-  int height = pDIB->GetHeight();
-  DCHECK(pdfium::base::IsValueInRangeForNumericType<uint32_t>(height));
-  return static_cast<uint32_t>(height) * pDIB->GetPitch() +
-         pDIB->GetRequiredPaletteSize() * 4;
-}
-
-}  // namespace
 
 CPDF_ImageCacheEntry::CPDF_ImageCacheEntry(CPDF_Document* pDoc,
                                            const RetainPtr<CPDF_Image>& pImage)
@@ -116,6 +100,9 @@
 }
 
 void CPDF_ImageCacheEntry::CalcSize() {
-  m_dwCacheSize = GetEstimatedImageSize(m_pCachedBitmap) +
-                  GetEstimatedImageSize(m_pCachedMask);
+  m_dwCacheSize = 0;
+  if (m_pCachedBitmap)
+    m_dwCacheSize += m_pCachedBitmap->GetEstimatedImageMemoryBurden();
+  if (m_pCachedMask)
+    m_dwCacheSize += m_pCachedMask->GetEstimatedImageMemoryBurden();
 }
diff --git a/core/fxge/dib/cfx_dibbase.cpp b/core/fxge/dib/cfx_dibbase.cpp
index 4eb0075..2bfae7a 100644
--- a/core/fxge/dib/cfx_dibbase.cpp
+++ b/core/fxge/dib/cfx_dibbase.cpp
@@ -612,6 +612,10 @@
   return false;
 }
 
+uint32_t CFX_DIBBase::GetEstimatedImageMemoryBurden() const {
+  return GetRequiredPaletteSize() * sizeof(uint32_t);
+}
+
 RetainPtr<CFX_DIBitmap> CFX_DIBBase::Clone(const FX_RECT* pClip) const {
   FX_RECT rect(0, 0, m_Width, m_Height);
   if (pClip) {
diff --git a/core/fxge/dib/cfx_dibbase.h b/core/fxge/dib/cfx_dibbase.h
index 705c3bf..8aee458 100644
--- a/core/fxge/dib/cfx_dibbase.h
+++ b/core/fxge/dib/cfx_dibbase.h
@@ -35,6 +35,7 @@
   virtual uint8_t* GetBuffer() const;
   virtual pdfium::span<const uint8_t> GetScanline(int line) const = 0;
   virtual bool SkipToScanline(int line, PauseIndicatorIface* pPause) const;
+  virtual uint32_t GetEstimatedImageMemoryBurden() const;
 
   pdfium::span<uint8_t> GetWritableScanline(int line) {
     pdfium::span<const uint8_t> src = GetScanline(line);
diff --git a/core/fxge/dib/cfx_dibitmap.cpp b/core/fxge/dib/cfx_dibitmap.cpp
index 96e3d49..d39f7f9 100644
--- a/core/fxge/dib/cfx_dibitmap.cpp
+++ b/core/fxge/dib/cfx_dibitmap.cpp
@@ -18,8 +18,10 @@
 #include "core/fxcrt/fx_safe_types.h"
 #include "core/fxge/cfx_cliprgn.h"
 #include "core/fxge/dib/cfx_scanlinecompositor.h"
+#include "third_party/base/check.h"
 #include "third_party/base/check_op.h"
 #include "third_party/base/notreached.h"
+#include "third_party/base/numerics/safe_conversions.h"
 
 CFX_DIBitmap::CFX_DIBitmap() = default;
 
@@ -104,6 +106,16 @@
   return {m_pBuffer.Get() + line * m_Pitch, m_Pitch};
 }
 
+uint32_t CFX_DIBitmap::GetEstimatedImageMemoryBurden() const {
+  uint32_t result = CFX_DIBBase::GetEstimatedImageMemoryBurden();
+  if (GetBuffer()) {
+    int height = GetHeight();
+    DCHECK(pdfium::base::IsValueInRangeForNumericType<uint32_t>(height));
+    result += static_cast<uint32_t>(height) * GetPitch();
+  }
+  return result;
+}
+
 void CFX_DIBitmap::TakeOver(RetainPtr<CFX_DIBitmap>&& pSrcBitmap) {
   m_pBuffer = std::move(pSrcBitmap->m_pBuffer);
   m_palette = std::move(pSrcBitmap->m_palette);
diff --git a/core/fxge/dib/cfx_dibitmap.h b/core/fxge/dib/cfx_dibitmap.h
index c3d9eb0..07c84c8 100644
--- a/core/fxge/dib/cfx_dibitmap.h
+++ b/core/fxge/dib/cfx_dibitmap.h
@@ -35,6 +35,7 @@
   // CFX_DIBBase
   uint8_t* GetBuffer() const override;
   pdfium::span<const uint8_t> GetScanline(int line) const override;
+  uint32_t GetEstimatedImageMemoryBurden() const override;
 
   void TakeOver(RetainPtr<CFX_DIBitmap>&& pSrcBitmap);
   bool ConvertFormat(FXDIB_Format format);