diff --git a/src/libImaging/Access.c b/src/libImaging/Access.c
index 3db52377e..65c832cbe 100644
--- a/src/libImaging/Access.c
+++ b/src/libImaging/Access.c
@@ -64,7 +64,7 @@ static void
 get_pixel_16L(Imaging im, int x, int y, void *color) {
     UINT8 *in = (UINT8 *)&im->image[y][x + x];
 #ifdef WORDS_BIGENDIAN
-    UINT16 out = in[0] + (in[1] << 8);
+    UINT16 out = in[0] + ((UINT16)in[1] << 8);
     memcpy(color, &out, sizeof(out));
 #else
     memcpy(color, in, sizeof(UINT16));
@@ -77,7 +77,7 @@ get_pixel_16B(Imaging im, int x, int y, void *color) {
 #ifdef WORDS_BIGENDIAN
     memcpy(color, in, sizeof(UINT16));
 #else
-    UINT16 out = in[1] + (in[0] << 8);
+    UINT16 out = in[1] + ((UINT16)in[0] << 8);
     memcpy(color, &out, sizeof(out));
 #endif
 }
@@ -91,7 +91,8 @@ static void
 get_pixel_32L(Imaging im, int x, int y, void *color) {
     UINT8 *in = (UINT8 *)&im->image[y][x * 4];
 #ifdef WORDS_BIGENDIAN
-    INT32 out = in[0] + (in[1] << 8) + (in[2] << 16) + (in[3] << 24);
+    INT32 out =
+        in[0] + ((INT32)in[1] << 8) + ((INT32)in[2] << 16) + ((INT32)in[3] << 24);
     memcpy(color, &out, sizeof(out));
 #else
     memcpy(color, in, sizeof(INT32));
@@ -104,7 +105,8 @@ get_pixel_32B(Imaging im, int x, int y, void *color) {
 #ifdef WORDS_BIGENDIAN
     memcpy(color, in, sizeof(INT32));
 #else
-    INT32 out = in[3] + (in[2] << 8) + (in[1] << 16) + (in[0] << 24);
+    INT32 out =
+        in[3] + ((INT32)in[2] << 8) + ((INT32)in[1] << 16) + ((INT32)in[0] << 24);
     memcpy(color, &out, sizeof(out));
 #endif
 }
diff --git a/src/libImaging/BcnEncode.c b/src/libImaging/BcnEncode.c
index 7a5072dde..861ae1c26 100644
--- a/src/libImaging/BcnEncode.c
+++ b/src/libImaging/BcnEncode.c
@@ -36,10 +36,9 @@ decode_565(UINT16 x) {
 
 static UINT16
 encode_565(rgba item) {
-    UINT8 r, g, b;
-    r = item.color[0] >> (8 - 5);
-    g = item.color[1] >> (8 - 6);
-    b = item.color[2] >> (8 - 5);
+    UINT16 r = item.color[0] >> (8 - 5);
+    UINT8 g = item.color[1] >> (8 - 6);
+    UINT8 b = item.color[2] >> (8 - 5);
     return (r << (5 + 6)) | (g << 5) | b;
 }
 
@@ -157,7 +156,8 @@ encode_bc1_color(Imaging im, ImagingCodecState state, UINT8 *dst, int separate_a
 static void
 encode_bc2_block(Imaging im, ImagingCodecState state, UINT8 *dst) {
     int i, j;
-    UINT8 block[16], current_alpha;
+    UINT8 block[16];
+    UINT32 current_alpha;
     for (i = 0; i < 4; i++) {
         for (j = 0; j < 4; j++) {
             int x = state->x + i * im->pixelsize;
diff --git a/src/libImaging/FliDecode.c b/src/libImaging/FliDecode.c
index 130ecb7f7..44994823e 100644
--- a/src/libImaging/FliDecode.c
+++ b/src/libImaging/FliDecode.c
@@ -16,9 +16,11 @@
 
 #include "Imaging.h"
 
-#define I16(ptr) ((ptr)[0] + ((ptr)[1] << 8))
+#define I16(ptr) ((ptr)[0] + ((int)(ptr)[1] << 8))
 
-#define I32(ptr) ((ptr)[0] + ((ptr)[1] << 8) + ((ptr)[2] << 16) + ((ptr)[3] << 24))
+#define I32(ptr)                                                   \
+    ((ptr)[0] + ((INT32)(ptr)[1] << 8) + ((INT32)(ptr)[2] << 16) + \
+     ((INT32)(ptr)[3] << 24))
 
 #define ERR_IF_DATA_OOB(offset)                 \
     if ((data + (offset)) > ptr + bytes) {      \
diff --git a/src/libImaging/GetBBox.c b/src/libImaging/GetBBox.c
index d430893dd..e50bd7140 100644
--- a/src/libImaging/GetBBox.c
+++ b/src/libImaging/GetBBox.c
@@ -212,7 +212,7 @@ ImagingGetExtrema(Imaging im, void *extrema) {
                 UINT16 v;
                 UINT8 *pixel = *im->image8;
 #ifdef WORDS_BIGENDIAN
-                v = pixel[0] + (pixel[1] << 8);
+                v = pixel[0] + ((UINT16)pixel[1] << 8);
 #else
                 memcpy(&v, pixel, sizeof(v));
 #endif
@@ -221,7 +221,7 @@ ImagingGetExtrema(Imaging im, void *extrema) {
                     for (x = 0; x < im->xsize; x++) {
                         pixel = (UINT8 *)im->image[y] + x * sizeof(v);
 #ifdef WORDS_BIGENDIAN
-                        v = pixel[0] + (pixel[1] << 8);
+                        v = pixel[0] + ((UINT16)pixel[1] << 8);
 #else
                         memcpy(&v, pixel, sizeof(v));
 #endif