diff --git a/_imaging.c b/_imaging.c
index 7b3380b40..a2db5c998 100644
--- a/_imaging.c
+++ b/_imaging.c
@@ -599,7 +599,7 @@ _fill(PyObject* self, PyObject* args)
     if (!PyArg_ParseTuple(args, "s|(ii)O", &mode, &xsize, &ysize, &color))
         return NULL;
 
-    im = ImagingNew(mode, xsize, ysize);
+    im = ImagingNewDirty(mode, xsize, ysize);
     if (!im)
         return NULL;
 
@@ -874,7 +874,7 @@ _gaussian_blur(ImagingObject* self, PyObject* args)
         return NULL;
 
     imIn = self->image;
-    imOut = ImagingNew(imIn->mode, imIn->xsize, imIn->ysize);
+    imOut = ImagingNewDirty(imIn->mode, imIn->xsize, imIn->ysize);
     if (!imOut)
         return NULL;
 
@@ -1539,7 +1539,7 @@ _resize(ImagingObject* self, PyObject* args)
         a[0] = (double) imIn->xsize / xsize;
         a[4] = (double) imIn->ysize / ysize;
 
-        imOut = ImagingNew(imIn->mode, xsize, ysize);
+        imOut = ImagingNewDirty(imIn->mode, xsize, ysize);
 
         imOut = ImagingTransform(
             imOut, imIn, IMAGING_TRANSFORM_AFFINE,
@@ -1665,12 +1665,12 @@ _transpose(ImagingObject* self, PyObject* args)
     case 0: /* flip left right */
     case 1: /* flip top bottom */
     case 3: /* rotate 180 */
-        imOut = ImagingNew(imIn->mode, imIn->xsize, imIn->ysize);
+        imOut = ImagingNewDirty(imIn->mode, imIn->xsize, imIn->ysize);
         break;
     case 2: /* rotate 90 */
     case 4: /* rotate 270 */
     case 5: /* transpose */
-        imOut = ImagingNew(imIn->mode, imIn->ysize, imIn->xsize);
+        imOut = ImagingNewDirty(imIn->mode, imIn->ysize, imIn->xsize);
         break;
     default:
         PyErr_SetString(PyExc_ValueError, "No such transpose operation");
@@ -1715,7 +1715,7 @@ _unsharp_mask(ImagingObject* self, PyObject* args)
         return NULL;
 
     imIn = self->image;
-    imOut = ImagingNew(imIn->mode, imIn->xsize, imIn->ysize);
+    imOut = ImagingNewDirty(imIn->mode, imIn->xsize, imIn->ysize);
     if (!imOut)
         return NULL;
 
@@ -1738,7 +1738,7 @@ _box_blur(ImagingObject* self, PyObject* args)
         return NULL;
 
     imIn = self->image;
-    imOut = ImagingNew(imIn->mode, imIn->xsize, imIn->ysize);
+    imOut = ImagingNewDirty(imIn->mode, imIn->xsize, imIn->ysize);
     if (!imOut)
         return NULL;
 
diff --git a/libImaging/AlphaComposite.c b/libImaging/AlphaComposite.c
index 538fd88e3..7e99c59ce 100644
--- a/libImaging/AlphaComposite.c
+++ b/libImaging/AlphaComposite.c
@@ -42,7 +42,7 @@ ImagingAlphaComposite(Imaging imDst, Imaging imSrc)
         imDst->ysize != imSrc->ysize)
         return ImagingError_Mismatch();
 
-    imOut = ImagingNew(imDst->mode, imDst->xsize, imDst->ysize);
+    imOut = ImagingNewDirty(imDst->mode, imDst->xsize, imDst->ysize);
     if (!imOut)
         return NULL;
 
diff --git a/libImaging/Bands.c b/libImaging/Bands.c
index d7424ab25..2fa6b8ebb 100644
--- a/libImaging/Bands.c
+++ b/libImaging/Bands.c
@@ -43,7 +43,7 @@ ImagingGetBand(Imaging imIn, int band)
     if (imIn->bands == 2 && band == 1)
         band = 3;
 
-    imOut = ImagingNew("L", imIn->xsize, imIn->ysize);
+    imOut = ImagingNewDirty("L", imIn->xsize, imIn->ysize);
     if (!imOut)
         return NULL;
 
diff --git a/libImaging/Blend.c b/libImaging/Blend.c
index 885a1bb82..919856714 100644
--- a/libImaging/Blend.c
+++ b/libImaging/Blend.c
@@ -40,7 +40,7 @@ ImagingBlend(Imaging imIn1, Imaging imIn2, float alpha)
     else if (alpha == 1.0)
 	return ImagingCopy(imIn2);
 
-    imOut = ImagingNew(imIn1->mode, imIn1->xsize, imIn1->ysize);
+    imOut = ImagingNewDirty(imIn1->mode, imIn1->xsize, imIn1->ysize);
     if (!imOut)
 	return NULL;
 
diff --git a/libImaging/BoxBlur.c b/libImaging/BoxBlur.c
index 854a53386..1a415ed16 100644
--- a/libImaging/BoxBlur.c
+++ b/libImaging/BoxBlur.c
@@ -265,7 +265,7 @@ ImagingBoxBlur(Imaging imOut, Imaging imIn, float radius, int n)
           strcmp(imIn->mode, "La") == 0))
         return ImagingError_ModeError();
 
-    imTransposed = ImagingNew(imIn->mode, imIn->ysize, imIn->xsize);
+    imTransposed = ImagingNewDirty(imIn->mode, imIn->ysize, imIn->xsize);
     if (!imTransposed)
         return NULL;
 
diff --git a/libImaging/Convert.c b/libImaging/Convert.c
index 0ec5ef864..f4253bda4 100644
--- a/libImaging/Convert.c
+++ b/libImaging/Convert.c
@@ -1035,7 +1035,7 @@ frompalette(Imaging imOut, Imaging imIn, const char *mode)
     else
         return (Imaging) ImagingError_ValueError("conversion not supported");
 
-    imOut = ImagingNew2(mode, imOut, imIn);
+    imOut = ImagingNew2Dirty(mode, imOut, imIn);
     if (!imOut)
         return NULL;
 
@@ -1073,7 +1073,7 @@ topalette(Imaging imOut, Imaging imIn, ImagingPalette inpalette, int dither)
     if (!palette)
         return (Imaging) ImagingError_ValueError("no palette");
 
-    imOut = ImagingNew2("P", imOut, imIn);
+    imOut = ImagingNew2Dirty("P", imOut, imIn);
     if (!imOut) {
       if (palette != inpalette)
         ImagingPaletteDelete(palette);
@@ -1211,7 +1211,7 @@ tobilevel(Imaging imOut, Imaging imIn, int dither)
     if (strcmp(imIn->mode, "L") != 0 && strcmp(imIn->mode, "RGB") != 0)
         return (Imaging) ImagingError_ValueError("conversion not supported");
 
-    imOut = ImagingNew2("1", imOut, imIn);
+    imOut = ImagingNew2Dirty("1", imOut, imIn);
     if (!imOut)
         return NULL;
 
@@ -1344,7 +1344,7 @@ convert(Imaging imOut, Imaging imIn, const char *mode,
     }
 #endif
 
-    imOut = ImagingNew2(mode, imOut, imIn);
+    imOut = ImagingNew2Dirty(mode, imOut, imIn);
     if (!imOut)
         return NULL;
 
@@ -1407,7 +1407,7 @@ ImagingConvertTransparent(Imaging imIn, const char *mode,
         g = b = r;
     }
 
-    imOut = ImagingNew2(mode, imOut, imIn);
+    imOut = ImagingNew2Dirty(mode, imOut, imIn);
     if (!imOut){
         return NULL;
     }
diff --git a/libImaging/Copy.c b/libImaging/Copy.c
index b5b0b0aea..992b8b505 100644
--- a/libImaging/Copy.c
+++ b/libImaging/Copy.c
@@ -28,7 +28,7 @@ _copy(Imaging imOut, Imaging imIn)
     if (!imIn)
 	return (Imaging) ImagingError_ValueError(NULL);
 
-    imOut = ImagingNew2(imIn->mode, imOut, imIn);
+    imOut = ImagingNew2Dirty(imIn->mode, imOut, imIn);
     if (!imOut)
         return NULL;
 
diff --git a/libImaging/Crop.c b/libImaging/Crop.c
index 0db67e8e9..893cdb5ba 100644
--- a/libImaging/Crop.c
+++ b/libImaging/Crop.c
@@ -37,7 +37,7 @@ ImagingCrop(Imaging imIn, int sx0, int sy0, int sx1, int sy1)
     if (ysize < 0)
         ysize = 0;
 
-    imOut = ImagingNew(imIn->mode, xsize, ysize);
+    imOut = ImagingNewDirty(imIn->mode, xsize, ysize);
     if (!imOut)
 	return NULL;
 
diff --git a/libImaging/Fill.c b/libImaging/Fill.c
index 15107b6d6..d641a5996 100644
--- a/libImaging/Fill.c
+++ b/libImaging/Fill.c
@@ -68,7 +68,7 @@ ImagingFillLinearGradient(const char *mode)
         return (Imaging) ImagingError_ModeError();
     }
 
-    im = ImagingNew(mode, 256, 256);
+    im = ImagingNewDirty(mode, 256, 256);
     if (!im) {
         return NULL;
     }
@@ -91,7 +91,7 @@ ImagingFillRadialGradient(const char *mode)
         return (Imaging) ImagingError_ModeError();
     }
 
-    im = ImagingNew(mode, 256, 256);
+    im = ImagingNewDirty(mode, 256, 256);
     if (!im) {
         return NULL;
     }
diff --git a/libImaging/Imaging.h b/libImaging/Imaging.h
index 35b563b1c..d46114133 100644
--- a/libImaging/Imaging.h
+++ b/libImaging/Imaging.h
@@ -159,7 +159,8 @@ struct ImagingPaletteInstance {
 extern int ImagingNewCount;
 
 extern Imaging ImagingNew(const char* mode, int xsize, int ysize);
-extern Imaging ImagingNew2(const char* mode, Imaging imOut, Imaging imIn);
+extern Imaging ImagingNewDirty(const char* mode, int xsize, int ysize);
+extern Imaging ImagingNew2Dirty(const char* mode, Imaging imOut, Imaging imIn);
 extern void    ImagingDelete(Imaging im);
 
 extern Imaging ImagingNewBlock(const char* mode, int xsize, int ysize);
diff --git a/libImaging/Matrix.c b/libImaging/Matrix.c
index 5d2f031cf..5cc7795a4 100644
--- a/libImaging/Matrix.c
+++ b/libImaging/Matrix.c
@@ -32,7 +32,7 @@ ImagingConvertMatrix(Imaging im, const char *mode, float m[])
 
     if (strcmp(mode, "L") == 0 && im->bands == 3) {
 
-	imOut = ImagingNew("L", im->xsize, im->ysize);
+	imOut = ImagingNewDirty("L", im->xsize, im->ysize);
 	if (!imOut)
 	    return NULL;
 
@@ -49,7 +49,7 @@ ImagingConvertMatrix(Imaging im, const char *mode, float m[])
 
     } else if (strlen(mode) == 3 && im->bands == 3) {
 
-	imOut = ImagingNew(mode, im->xsize, im->ysize);
+	imOut = ImagingNewDirty(mode, im->xsize, im->ysize);
 	if (!imOut)
 	    return NULL;
 
diff --git a/libImaging/Negative.c b/libImaging/Negative.c
index eaa790768..4dedcb245 100644
--- a/libImaging/Negative.c
+++ b/libImaging/Negative.c
@@ -29,7 +29,7 @@ ImagingNegative(Imaging im)
     if (!im)
 	return (Imaging) ImagingError_ModeError();
 
-    imOut = ImagingNew(im->mode, im->xsize, im->ysize);
+    imOut = ImagingNewDirty(im->mode, im->xsize, im->ysize);
     if (!imOut)
 	return NULL;
 
diff --git a/libImaging/Offset.c b/libImaging/Offset.c
index f6d6e510e..7d69f38a7 100644
--- a/libImaging/Offset.c
+++ b/libImaging/Offset.c
@@ -27,7 +27,7 @@ ImagingOffset(Imaging im, int xoffset, int yoffset)
     if (!im)
 	return (Imaging) ImagingError_ModeError();
 
-    imOut = ImagingNew(im->mode, im->xsize, im->ysize);
+    imOut = ImagingNewDirty(im->mode, im->xsize, im->ysize);
     if (!imOut)
 	return NULL;
 
diff --git a/libImaging/Resample.c b/libImaging/Resample.c
index 00918bb49..afd045f7a 100644
--- a/libImaging/Resample.c
+++ b/libImaging/Resample.c
@@ -256,7 +256,7 @@ ImagingResampleHorizontal_8bpc(Imaging imIn, int xsize, struct filter *filterp)
         return (Imaging) ImagingError_MemoryError();
     }
 
-    imOut = ImagingNew(imIn->mode, xsize, imIn->ysize);
+    imOut = ImagingNewDirty(imIn->mode, xsize, imIn->ysize);
     if ( ! imOut) {
         free(kk);
         free(xbounds);
@@ -358,7 +358,7 @@ ImagingResampleVertical_8bpc(Imaging imIn, int ysize, struct filter *filterp)
         return (Imaging) ImagingError_MemoryError();
     }
 
-    imOut = ImagingNew(imIn->mode, imIn->xsize, ysize);
+    imOut = ImagingNewDirty(imIn->mode, imIn->xsize, ysize);
     if ( ! imOut) {
         free(kk);
         free(xbounds);
@@ -452,7 +452,7 @@ ImagingResampleHorizontal_32bpc(Imaging imIn, int xsize, struct filter *filterp)
         return (Imaging) ImagingError_MemoryError();
     }
 
-    imOut = ImagingNew(imIn->mode, xsize, imIn->ysize);
+    imOut = ImagingNewDirty(imIn->mode, xsize, imIn->ysize);
     if ( ! imOut) {
         free(kk);
         free(xbounds);
@@ -512,7 +512,7 @@ ImagingResampleVertical_32bpc(Imaging imIn, int ysize, struct filter *filterp)
         return (Imaging) ImagingError_MemoryError();
     }
 
-    imOut = ImagingNew(imIn->mode, imIn->xsize, ysize);
+    imOut = ImagingNewDirty(imIn->mode, imIn->xsize, ysize);
     if ( ! imOut) {
         free(kk);
         free(xbounds);
diff --git a/libImaging/Storage.c b/libImaging/Storage.c
index 3c365207d..615c5fa20 100644
--- a/libImaging/Storage.c
+++ b/libImaging/Storage.c
@@ -277,7 +277,7 @@ ImagingDestroyArray(Imaging im)
 }
 
 Imaging
-ImagingAllocateArray(Imaging im)
+ImagingAllocateArray(Imaging im, int dirty)
 {
     ImagingSectionCookie cookie;
 
@@ -289,7 +289,11 @@ ImagingAllocateArray(Imaging im)
     /* Allocate image as an array of lines */
     for (y = 0; y < im->ysize; y++) {
         /* malloc check linesize checked in prologue */
-        p = (char *) calloc(1, im->linesize);
+        if (dirty) {
+            p = (char *) malloc(im->linesize);
+        } else {
+            p = (char *) calloc(1, im->linesize);
+        }
         if (!p) {
             ImagingDestroyArray(im);
             break;
@@ -321,7 +325,7 @@ ImagingDestroyBlock(Imaging im)
 }
 
 Imaging
-ImagingAllocateBlock(Imaging im)
+ImagingAllocateBlock(Imaging im, int dirty)
 {
     Py_ssize_t y, i;
 
@@ -341,8 +345,13 @@ ImagingAllocateBlock(Imaging im)
            platforms */
         im->block = (char *) malloc(1);
     } else {
-        /* malloc check ok, overflow check above */
-        im->block = (char *) calloc(im->ysize, im->linesize);
+        if (dirty) {
+            /* malloc check ok, overflow check above */
+            im->block = (char *) malloc(im->ysize * im->linesize);
+        } else {
+            /* malloc check ok, overflow check above */
+            im->block = (char *) calloc(im->ysize, im->linesize);
+        }
     }
 
     if ( ! im->block) {
@@ -369,7 +378,7 @@ ImagingAllocateBlock(Imaging im)
 #endif
 
 Imaging
-ImagingNew(const char* mode, int xsize, int ysize)
+ImagingNewInternal(const char* mode, int xsize, int ysize, int dirty)
 {
     Imaging im;
 
@@ -382,14 +391,14 @@ ImagingNew(const char* mode, int xsize, int ysize)
         return NULL;
 
     if (im->ysize && im->linesize <= THRESHOLD / im->ysize) {
-        if (ImagingAllocateBlock(im)) {
+        if (ImagingAllocateBlock(im, dirty)) {
             return im;
         }
         /* assume memory error; try allocating in array mode instead */
         ImagingError_Clear();
     }
 
-    if (ImagingAllocateArray(im)) {
+    if (ImagingAllocateArray(im, dirty)) {
         return im;
     }
 
@@ -397,6 +406,18 @@ ImagingNew(const char* mode, int xsize, int ysize)
     return NULL;
 }
 
+Imaging
+ImagingNew(const char* mode, int xsize, int ysize)
+{
+    return ImagingNewInternal(mode, xsize, ysize, 0);
+}
+
+Imaging
+ImagingNewDirty(const char* mode, int xsize, int ysize)
+{
+    return ImagingNewInternal(mode, xsize, ysize, 1);
+}
+
 Imaging
 ImagingNewBlock(const char* mode, int xsize, int ysize)
 {
@@ -406,7 +427,7 @@ ImagingNewBlock(const char* mode, int xsize, int ysize)
     if ( ! im)
         return NULL;
 
-    if (ImagingAllocateBlock(im)) {
+    if (ImagingAllocateBlock(im, 0)) {
         return im;
     }
 
@@ -415,7 +436,7 @@ ImagingNewBlock(const char* mode, int xsize, int ysize)
 }
 
 Imaging
-ImagingNew2(const char* mode, Imaging imOut, Imaging imIn)
+ImagingNew2Dirty(const char* mode, Imaging imOut, Imaging imIn)
 {
     /* allocate or validate output image */
 
@@ -428,7 +449,7 @@ ImagingNew2(const char* mode, Imaging imOut, Imaging imIn)
         }
     } else {
         /* create new image */
-        imOut = ImagingNew(mode, imIn->xsize, imIn->ysize);
+        imOut = ImagingNewDirty(mode, imIn->xsize, imIn->ysize);
         if (!imOut)
             return NULL;
     }