--- WebCore/platform/graphics/BitmapImage.cpp
+++ WebCore/platform/graphics/BitmapImage.cpp
@@ -203,7 +203,7 @@ float BitmapImage::frameDurationAtIndex(size_t index)
 bool BitmapImage::frameHasAlphaAtIndex(size_t index)
 {
     if (index >= frameCount())
-        return 0;
+        return true;
 
     if (index >= m_frames.size() || !m_frames[index].m_frame)
         cacheFrame(index);
--- WebCore/platform/graphics/cairo/ImageCairo.cpp
+++ WebCore/platform/graphics/cairo/ImageCairo.cpp
@@ -76,6 +76,7 @@ BitmapImage::BitmapImage(cairo_surface_t* surface, ImageObserver* observer)
 
     m_frames.grow(1);
     m_frames[0].m_frame = surface;
+    m_frames[0].m_hasAlpha = cairo_surface_get_content(surface) != CAIRO_CONTENT_COLOR;
     checkForSolidColor();
 }
 
--- WebCore/platform/graphics/cg/ImageCG.cpp
+++ WebCore/platform/graphics/cg/ImageCG.cpp
@@ -87,6 +87,7 @@ BitmapImage::BitmapImage(CGImageRef cgImage, ImageObserver* observer)
 
     m_frames.grow(1);
     m_frames[0].m_frame = cgImage;
+    m_frames[0].m_hasAlpha = true;
     checkForSolidColor();
 }