diff --git a/src/libImaging/QuantHeap.c b/src/libImaging/QuantHeap.c
index 121b87275..498d44b1d 100644
--- a/src/libImaging/QuantHeap.c
+++ b/src/libImaging/QuantHeap.c
@@ -26,8 +26,8 @@
 
 struct _Heap {
    void **heap;
-   int heapsize;
-   int heapcount;
+   unsigned int heapsize;
+   unsigned int heapcount;
    HeapCmpFunc cf;
 };
 
@@ -44,7 +44,7 @@ void ImagingQuantHeapFree(Heap *h) {
    free(h);
 }
 
-static int _heap_grow(Heap *h,int newsize) {
+static int _heap_grow(Heap *h,unsigned int newsize) {
    void *newheap;
    if (!newsize) newsize=h->heapsize<<1;
    if (newsize<h->heapsize) return 0;
@@ -64,7 +64,7 @@ static int _heap_grow(Heap *h,int newsize) {
 
 #ifdef DEBUG
 static int _heap_test(Heap *h) {
-   int k;
+   unsigned int k;
    for (k=1;k*2<=h->heapcount;k++) {
       if (h->cf(h,h->heap[k],h->heap[k*2])<0) {
          printf ("heap is bad\n");
@@ -80,7 +80,7 @@ static int _heap_test(Heap *h) {
 #endif
 
 int ImagingQuantHeapRemove(Heap* h,void **r) {
-   int k,l;
+   unsigned int k,l;
    void *v;
 
    if (!h->heapcount) {
diff --git a/src/libImaging/QuantOctree.c b/src/libImaging/QuantOctree.c
index 6c0f605c9..83d987544 100644
--- a/src/libImaging/QuantOctree.c
+++ b/src/libImaging/QuantOctree.c
@@ -44,7 +44,7 @@ typedef struct _ColorCube{
    unsigned int rWidth, gWidth, bWidth, aWidth;
    unsigned int rOffset, gOffset, bOffset, aOffset;
 
-   long size;
+   unsigned long size;
    ColorBucket buckets;
 } *ColorCube;
 
@@ -134,10 +134,10 @@ add_color_to_color_cube(const ColorCube cube, const Pixel *p) {
    bucket->a += p->c.a;
 }
 
-static long
+static unsigned long
 count_used_color_buckets(const ColorCube cube) {
-   long usedBuckets = 0;
-   long i;
+   unsigned long usedBuckets = 0;
+   unsigned long i;
    for (i=0; i < cube->size; i++) {
       if (cube->buckets[i].count > 0) {
          usedBuckets += 1;
@@ -194,7 +194,7 @@ void add_bucket_values(ColorBucket src, ColorBucket dst) {
 
 /* expand or shrink a given cube to level */
 static ColorCube copy_color_cube(const ColorCube cube,
-   int rBits, int gBits, int bBits, int aBits)
+   unsigned int rBits, unsigned int gBits, unsigned int bBits, unsigned int aBits)
 {
    unsigned int r, g, b, a;
    long src_pos, dst_pos;
@@ -302,7 +302,7 @@ void add_lookup_buckets(ColorCube cube, ColorBucket palette, long nColors, long
 }
 
 ColorBucket
-combined_palette(ColorBucket bucketsA, long nBucketsA, ColorBucket bucketsB, long nBucketsB) {
+combined_palette(ColorBucket bucketsA, unsigned long nBucketsA, ColorBucket bucketsB, unsigned long nBucketsB) {
    ColorBucket result;
    if (nBucketsA > LONG_MAX - nBucketsB ||
        (nBucketsA+nBucketsB) > LONG_MAX / sizeof(struct _ColorBucket)) {
@@ -345,8 +345,8 @@ map_image_pixels(const Pixel *pixelData,
    }
 }
 
-const int CUBE_LEVELS[8]       = {4, 4, 4, 0, 2, 2, 2, 0};
-const int CUBE_LEVELS_ALPHA[8] = {3, 4, 3, 3, 2, 2, 2, 2};
+const unsigned int CUBE_LEVELS[8]       = {4, 4, 4, 0, 2, 2, 2, 0};
+const unsigned int CUBE_LEVELS_ALPHA[8] = {3, 4, 3, 3, 2, 2, 2, 2};
 
 int quantize_octree(Pixel *pixelData,
           uint32_t nPixels,
@@ -365,8 +365,8 @@ int quantize_octree(Pixel *pixelData,
    ColorBucket paletteBuckets = NULL;
    uint32_t *qp = NULL;
    long i;
-   long nCoarseColors, nFineColors, nAlreadySubtracted;
-   const int *cubeBits;
+   unsigned long nCoarseColors, nFineColors, nAlreadySubtracted;
+   const unsigned int *cubeBits;
 
    if (withAlpha) {
        cubeBits = CUBE_LEVELS_ALPHA;