diff --git a/src/zm_image.cpp b/src/zm_image.cpp
index af5c0133e..16c528eee 100644
--- a/src/zm_image.cpp
+++ b/src/zm_image.cpp
@@ -181,12 +181,20 @@ void Image::Initialise()
 			Debug(2,"Delta: Using SSSE3 delta functions");
 		} else if(sseversion >= 20) {
 			/* SSE2 available */
-			fptr_delta8_rgba = &std_delta8_rgba;
-			fptr_delta8_bgra = &std_delta8_bgra;
-			fptr_delta8_argb = &std_delta8_argb;
-			fptr_delta8_abgr = &std_delta8_abgr;
+			fptr_delta8_rgba = &sse2_delta8_rgba;
+			fptr_delta8_bgra = &sse2_delta8_bgra;
+			fptr_delta8_argb = &sse2_delta8_argb;
+			fptr_delta8_abgr = &sse2_delta8_abgr;
+			/* On some systems, the 4 SSE2 algorithms above might be slower than
+			** the standard algorithms, especially on early Pentium 4 processors
+			** In that case, comment out the 4 lines above and uncomment the 4 lines below
+			*/
+			// fptr_delta8_rgba = &std_delta8_rgba;
+			// fptr_delta8_bgra = &std_delta8_bgra;
+			// fptr_delta8_argb = &std_delta8_argb;
+			// fptr_delta8_abgr = &std_delta8_abgr;
 			fptr_delta8_gray8 = &sse2_delta8_gray8;
-			Debug(2,"Delta: Using standard and SSE2 delta functions");
+			Debug(2,"Delta: Using SSE2 delta functions");
 		} else {
 			/* No SSE available */
 			fptr_delta8_rgba = &std_delta8_rgba;
@@ -2403,7 +2411,7 @@ __attribute__ ((noinline)) void sse2_fastblend(const uint8_t* col1, const uint8_
 	"cmp %3, %4\n\t"
 	"jb algo_sse2_blend\n\t"
 	:
-	: "r" (col1), "r" (col2), "r" (result), "r" (count), "r" (i), "m" (clearmask), "m" (divider)
+	: "r" (col1), "r" (col2), "r" (result), "m" (count), "r" (i), "m" (clearmask), "m" (divider)
 	: "%xmm0", "%xmm1", "%xmm2", "%xmm3", "%xmm4", "cc", "memory"
 	);
 #else
@@ -2666,7 +2674,7 @@ __attribute__ ((noinline)) void sse2_delta8_gray8(const uint8_t* col1, const uin
 	"cmp %3, %4\n\t"
 	"jb algo_sse2_delta8_gray8\n\t"
 	:
-	: "r" (col1), "r" (col2), "r" (result), "r" (count), "r" (i)
+	: "r" (col1), "r" (col2), "r" (result), "m" (count), "r" (i)
 	: "%xmm1", "%xmm2", "%xmm3", "%xmm4", "cc", "memory"
 	);
 #else
@@ -2674,6 +2682,308 @@ __attribute__ ((noinline)) void sse2_delta8_gray8(const uint8_t* col1, const uin
 #endif
 }
 
+/* RGB32: RGBA SSE2 */
+__attribute__ ((noinline)) void sse2_delta8_rgba(const uint8_t* col1, const uint8_t* col2, uint8_t* result, unsigned long count) {
+#if (defined(__i386__) || defined(__x86_64__))  
+	unsigned long i = 0;
+
+	/* XMM0 - clear mask - kept */
+	/* XMM1,2,3 - General purpose */
+	/* XMM4 - divide mask - kept */
+	/* XMM5 - temp */
+	/* XMM6 - temp */
+	/* XMM7 - unused */  
+  
+	__asm__ __volatile__ (
+	"mov $0x1F1F1F1F, %%eax\n\t"
+	"movd %%eax, %%xmm4\n\t"
+	"pshufd $0x0, %%xmm4, %%xmm4\n\t"
+	"mov $0xff, %%eax\n\t"
+	"movd %%eax, %%xmm0\n\t"
+	"pshufd $0x0, %%xmm0, %%xmm0\n\t"
+	"mov $0x80000000, %%eax\n\t"
+	"movd %%eax, %%xmm5\n\t"
+	"pshufd $0x0, %%xmm5, %%xmm5\n\t"
+	"algo_sse2_delta8_rgba:\n\t"
+	"movdqa (%0,%4,4), %%xmm1\n\t"
+	"movdqa (%1,%4,4), %%xmm2\n\t"
+	"psrlq $0x3, %%xmm1\n\t"
+	"psrlq $0x3, %%xmm2\n\t"
+	"pand %%xmm4, %%xmm1\n\t"
+	"pand %%xmm4, %%xmm2\n\t"
+	"movdqa %%xmm1, %%xmm5\n\t"
+	"movdqa %%xmm2, %%xmm6\n\t"
+	"pmaxub %%xmm1, %%xmm2\n\t"
+	"pminub %%xmm5, %%xmm6\n\t"
+	"psubb %%xmm6, %%xmm2\n\t"
+	"movdqa %%xmm2, %%xmm3\n\t"
+	"psrld $0x8, %%xmm2\n\t"
+	"pand %%xmm0, %%xmm2\n\t"
+	"movdqa %%xmm2, %%xmm1\n\t"
+	"pslld $0x2, %%xmm2\n\t"
+	"paddd %%xmm1, %%xmm2\n\t"
+	"movdqa %%xmm3, %%xmm1\n\t"
+	"pand %%xmm0, %%xmm1\n\t"
+	"paddd %%xmm1, %%xmm1\n\t"
+	"paddd %%xmm2, %%xmm1\n\t"
+	"movdqa %%xmm3, %%xmm2\n\t"
+	"psrld $0x10, %%xmm2\n\t"
+	"pand %%xmm0, %%xmm2\n\t"
+	"paddd %%xmm2, %%xmm1\n\t"
+	"movdqa %%xmm1, %%xmm3\n\t"
+	"movdqa %%xmm1, %%xmm2\n\t"
+	"pand %%xmm0, %%xmm3\n\t"
+	"pand %%xmm0, %%xmm2\n\t"
+	"psrldq $0x9, %%xmm2\n\t"
+	"por %%xmm2, %%xmm3\n\t"
+	"movdqa %%xmm1, %%xmm2\n\t"
+	"pand %%xmm0, %%xmm2\n\t"
+	"psrldq $0x6, %%xmm2\n\t"
+	"por %%xmm2, %%xmm3\n\t"
+	"pand %%xmm0, %%xmm1\n\t"
+	"psrldq $0x3, %%xmm1\n\t"
+	"por %%xmm1, %%xmm3\n\t"
+	"movd %%xmm3, %%eax\n\t"
+	"movnti %%eax, (%2,%4)\n\t"
+	"add $0x4, %4\n\t"
+	"cmp %3, %4\n\t"
+	"jb algo_sse2_delta8_rgba\n\t"
+	:
+	: "r" (col1), "r" (col2), "r" (result), "m" (count), "r" (i)
+	: "%eax", "%xmm0", "%xmm1", "%xmm2", "%xmm3", "%xmm4", "%xmm5", "%xmm6", "cc", "memory"
+	);
+#else
+	Panic("SSE function called on a non x86\\x86-64 platform");
+#endif
+}
+
+/* RGB32: BGRA SSE2 */
+__attribute__ ((noinline)) void sse2_delta8_bgra(const uint8_t* col1, const uint8_t* col2, uint8_t* result, unsigned long count) {
+#if (defined(__i386__) || defined(__x86_64__))  
+	unsigned long i = 0;
+
+	/* XMM0 - clear mask - kept */
+	/* XMM1,2,3 - General purpose */
+	/* XMM4 - divide mask - kept */
+	/* XMM5 - temp */
+	/* XMM6 - temp */
+	/* XMM7 - unused */  
+  
+	__asm__ __volatile__ (
+	"mov $0x1F1F1F1F, %%eax\n\t"
+	"movd %%eax, %%xmm4\n\t"
+	"pshufd $0x0, %%xmm4, %%xmm4\n\t"
+	"mov $0xff, %%eax\n\t"
+	"movd %%eax, %%xmm0\n\t"
+	"pshufd $0x0, %%xmm0, %%xmm0\n\t"
+	"mov $0x80000000, %%eax\n\t"
+	"movd %%eax, %%xmm5\n\t"
+	"pshufd $0x0, %%xmm5, %%xmm5\n\t"
+	"algo_sse2_delta8_bgra:\n\t"
+	"movdqa (%0,%4,4), %%xmm1\n\t"
+	"movdqa (%1,%4,4), %%xmm2\n\t"
+	"psrlq $0x3, %%xmm1\n\t"
+	"psrlq $0x3, %%xmm2\n\t"
+	"pand %%xmm4, %%xmm1\n\t"
+	"pand %%xmm4, %%xmm2\n\t"
+	"movdqa %%xmm1, %%xmm5\n\t"
+	"movdqa %%xmm2, %%xmm6\n\t"
+	"pmaxub %%xmm1, %%xmm2\n\t"
+	"pminub %%xmm5, %%xmm6\n\t"
+	"psubb %%xmm6, %%xmm2\n\t"
+	"movdqa %%xmm2, %%xmm3\n\t"
+	"psrld $0x8, %%xmm2\n\t"
+	"pand %%xmm0, %%xmm2\n\t"
+	"movdqa %%xmm2, %%xmm1\n\t"
+	"pslld $0x2, %%xmm2\n\t"
+	"paddd %%xmm1, %%xmm2\n\t"
+	"movdqa %%xmm3, %%xmm1\n\t"
+	"pand %%xmm0, %%xmm1\n\t"
+	"paddd %%xmm2, %%xmm1\n\t"
+	"movdqa %%xmm3, %%xmm2\n\t"
+	"psrld $0x10, %%xmm2\n\t"
+	"pand %%xmm0, %%xmm2\n\t"
+	"paddd %%xmm2, %%xmm2\n\t"
+	"paddd %%xmm2, %%xmm1\n\t"
+	"movdqa %%xmm1, %%xmm3\n\t"
+	"movdqa %%xmm1, %%xmm2\n\t"
+	"pand %%xmm0, %%xmm3\n\t"
+	"pand %%xmm0, %%xmm2\n\t"
+	"psrldq $0x9, %%xmm2\n\t"
+	"por %%xmm2, %%xmm3\n\t"
+	"movdqa %%xmm1, %%xmm2\n\t"
+	"pand %%xmm0, %%xmm2\n\t"
+	"psrldq $0x6, %%xmm2\n\t"
+	"por %%xmm2, %%xmm3\n\t"
+	"pand %%xmm0, %%xmm1\n\t"
+	"psrldq $0x3, %%xmm1\n\t"
+	"por %%xmm1, %%xmm3\n\t"
+	"movd %%xmm3, %%eax\n\t"
+	"movnti %%eax, (%2,%4)\n\t"
+	"add $0x4, %4\n\t"
+	"cmp %3, %4\n\t"
+	"jb algo_sse2_delta8_bgra\n\t"
+	:
+	: "r" (col1), "r" (col2), "r" (result), "m" (count), "r" (i)
+	: "%eax", "%xmm0", "%xmm1", "%xmm2", "%xmm3", "%xmm4", "%xmm5", "%xmm6", "cc", "memory"
+	);
+#else
+	Panic("SSE function called on a non x86\\x86-64 platform");
+#endif
+}
+
+/* RGB32: ARGB SSE2 */
+__attribute__ ((noinline)) void sse2_delta8_argb(const uint8_t* col1, const uint8_t* col2, uint8_t* result, unsigned long count) {
+#if (defined(__i386__) || defined(__x86_64__))  
+	unsigned long i = 0;
+
+	/* XMM0 - clear mask - kept */
+	/* XMM1,2,3 - General purpose */
+	/* XMM4 - divide mask - kept */
+	/* XMM5 - temp */
+	/* XMM6 - temp */
+	/* XMM7 - unused */  
+  
+	__asm__ __volatile__ (
+	"mov $0x1F1F1F1F, %%eax\n\t"
+	"movd %%eax, %%xmm4\n\t"
+	"pshufd $0x0, %%xmm4, %%xmm4\n\t"
+	"mov $0xff, %%eax\n\t"
+	"movd %%eax, %%xmm0\n\t"
+	"pshufd $0x0, %%xmm0, %%xmm0\n\t"
+	"mov $0x80000000, %%eax\n\t"
+	"movd %%eax, %%xmm5\n\t"
+	"pshufd $0x0, %%xmm5, %%xmm5\n\t"
+	"algo_sse2_delta8_argb:\n\t"
+	"movdqa (%0,%4,4), %%xmm1\n\t"
+	"movdqa (%1,%4,4), %%xmm2\n\t"
+	"psrlq $0x3, %%xmm1\n\t"
+	"psrlq $0x3, %%xmm2\n\t"
+	"pand %%xmm4, %%xmm1\n\t"
+	"pand %%xmm4, %%xmm2\n\t"
+	"movdqa %%xmm1, %%xmm5\n\t"
+	"movdqa %%xmm2, %%xmm6\n\t"
+	"pmaxub %%xmm1, %%xmm2\n\t"
+	"pminub %%xmm5, %%xmm6\n\t"
+	"psubb %%xmm6, %%xmm2\n\t"
+	"movdqa %%xmm2, %%xmm3\n\t"
+	"psrld $0x10, %%xmm2\n\t"
+	"pand %%xmm0, %%xmm2\n\t"
+	"movdqa %%xmm2, %%xmm1\n\t"
+	"pslld $0x2, %%xmm2\n\t"
+	"paddd %%xmm1, %%xmm2\n\t"
+	"movdqa %%xmm3, %%xmm1\n\t"
+	"psrld $0x8, %%xmm1\n\t"
+	"pand %%xmm0, %%xmm1\n\t"
+	"paddd %%xmm1, %%xmm1\n\t"
+	"paddd %%xmm2, %%xmm1\n\t"
+	"movdqa %%xmm3, %%xmm2\n\t"
+	"psrld $0x18, %%xmm2\n\t"
+	"pand %%xmm0, %%xmm2\n\t"
+	"paddd %%xmm2, %%xmm1\n\t"
+	"movdqa %%xmm1, %%xmm3\n\t"
+	"movdqa %%xmm1, %%xmm2\n\t"
+	"pand %%xmm0, %%xmm3\n\t"
+	"pand %%xmm0, %%xmm2\n\t"
+	"psrldq $0x9, %%xmm2\n\t"
+	"por %%xmm2, %%xmm3\n\t"
+	"movdqa %%xmm1, %%xmm2\n\t"
+	"pand %%xmm0, %%xmm2\n\t"
+	"psrldq $0x6, %%xmm2\n\t"
+	"por %%xmm2, %%xmm3\n\t"
+	"pand %%xmm0, %%xmm1\n\t"
+	"psrldq $0x3, %%xmm1\n\t"
+	"por %%xmm1, %%xmm3\n\t"
+	"movd %%xmm3, %%eax\n\t"
+	"movnti %%eax, (%2,%4)\n\t"
+	"add $0x4, %4\n\t"
+	"cmp %3, %4\n\t"
+	"jb algo_sse2_delta8_argb\n\t"
+	:
+	: "r" (col1), "r" (col2), "r" (result), "m" (count), "r" (i)
+	: "%eax", "%xmm0", "%xmm1", "%xmm2", "%xmm3", "%xmm4", "%xmm5", "%xmm6", "cc", "memory"
+	);
+#else
+	Panic("SSE function called on a non x86\\x86-64 platform");
+#endif
+}
+
+/* RGB32: ABGR SSE2 */
+__attribute__ ((noinline)) void sse2_delta8_abgr(const uint8_t* col1, const uint8_t* col2, uint8_t* result, unsigned long count) {
+#if (defined(__i386__) || defined(__x86_64__))  
+	unsigned long i = 0;
+
+	/* XMM0 - clear mask - kept */
+	/* XMM1,2,3 - General purpose */
+	/* XMM4 - divide mask - kept */
+	/* XMM5 - temp */
+	/* XMM6 - temp */
+	/* XMM7 - unused */  
+  
+	__asm__ __volatile__ (
+	"mov $0x1F1F1F1F, %%eax\n\t"
+	"movd %%eax, %%xmm4\n\t"
+	"pshufd $0x0, %%xmm4, %%xmm4\n\t"
+	"mov $0xff, %%eax\n\t"
+	"movd %%eax, %%xmm0\n\t"
+	"pshufd $0x0, %%xmm0, %%xmm0\n\t"
+	"mov $0x80000000, %%eax\n\t"
+	"movd %%eax, %%xmm5\n\t"
+	"pshufd $0x0, %%xmm5, %%xmm5\n\t"
+	"algo_sse2_delta8_abgr:\n\t"
+	"movdqa (%0,%4,4), %%xmm1\n\t"
+	"movdqa (%1,%4,4), %%xmm2\n\t"
+	"psrlq $0x3, %%xmm1\n\t"
+	"psrlq $0x3, %%xmm2\n\t"
+	"pand %%xmm4, %%xmm1\n\t"
+	"pand %%xmm4, %%xmm2\n\t"
+	"movdqa %%xmm1, %%xmm5\n\t"
+	"movdqa %%xmm2, %%xmm6\n\t"
+	"pmaxub %%xmm1, %%xmm2\n\t"
+	"pminub %%xmm5, %%xmm6\n\t"
+	"psubb %%xmm6, %%xmm2\n\t"
+	"movdqa %%xmm2, %%xmm3\n\t"
+	"psrld $0x10, %%xmm2\n\t"
+	"pand %%xmm0, %%xmm2\n\t"
+	"movdqa %%xmm2, %%xmm1\n\t"
+	"pslld $0x2, %%xmm2\n\t"
+	"paddd %%xmm1, %%xmm2\n\t"
+	"movdqa %%xmm3, %%xmm1\n\t"
+	"psrld $0x8, %%xmm1\n\t"
+	"pand %%xmm0, %%xmm1\n\t"
+	"paddd %%xmm2, %%xmm1\n\t"
+	"movdqa %%xmm3, %%xmm2\n\t"
+	"psrld $0x18, %%xmm2\n\t"
+	"pand %%xmm0, %%xmm2\n\t"
+	"paddd %%xmm2, %%xmm2\n\t"
+	"paddd %%xmm2, %%xmm1\n\t"
+	"movdqa %%xmm1, %%xmm3\n\t"
+	"movdqa %%xmm1, %%xmm2\n\t"
+	"pand %%xmm0, %%xmm3\n\t"
+	"pand %%xmm0, %%xmm2\n\t"
+	"psrldq $0x9, %%xmm2\n\t"
+	"por %%xmm2, %%xmm3\n\t"
+	"movdqa %%xmm1, %%xmm2\n\t"
+	"pand %%xmm0, %%xmm2\n\t"
+	"psrldq $0x6, %%xmm2\n\t"
+	"por %%xmm2, %%xmm3\n\t"
+	"pand %%xmm0, %%xmm1\n\t"
+	"psrldq $0x3, %%xmm1\n\t"
+	"por %%xmm1, %%xmm3\n\t"
+	"movd %%xmm3, %%eax\n\t"
+	"movnti %%eax, (%2,%4)\n\t"
+	"add $0x4, %4\n\t"
+	"cmp %3, %4\n\t"
+	"jb algo_sse2_delta8_abgr\n\t"
+	:
+	: "r" (col1), "r" (col2), "r" (result), "m" (count), "r" (i)
+	: "%eax", "%xmm0", "%xmm1", "%xmm2", "%xmm3", "%xmm4", "%xmm5", "%xmm6", "cc", "memory"
+	);
+#else
+	Panic("SSE function called on a non x86\\x86-64 platform");
+#endif
+}
+
 /* RGB32: RGBA SSSE3 */
 __attribute__ ((noinline)) void ssse3_delta8_rgba(const uint8_t* col1, const uint8_t* col2, uint8_t* result, unsigned long count) {
 #if (defined(__i386__) || defined(__x86_64__))
@@ -2724,7 +3034,7 @@ __attribute__ ((noinline)) void ssse3_delta8_rgba(const uint8_t* col1, const uin
 	"cmp %3, %4\n\t"
 	"jb algo_ssse3_delta8_rgba\n\t"
 	:
-	: "r" (col1), "r" (col2), "r" (result), "r" (count), "r" (i), "m" (*movemask)
+	: "r" (col1), "r" (col2), "r" (result), "m" (count), "r" (i), "m" (*movemask)
 	: "%eax", "%xmm0", "%xmm1", "%xmm2", "%xmm3", "%xmm4", "%xmm5", "cc", "memory"
 	);
 #else
@@ -2782,7 +3092,7 @@ __attribute__ ((noinline)) void ssse3_delta8_bgra(const uint8_t* col1, const uin
 	"cmp %3, %4\n\t"
 	"jb algo_ssse3_delta8_bgra\n\t"
 	:
-	: "r" (col1), "r" (col2), "r" (result), "r" (count), "r" (i), "m" (*movemask)
+	: "r" (col1), "r" (col2), "r" (result), "m" (count), "r" (i), "m" (*movemask)
 	: "%eax", "%xmm0", "%xmm1", "%xmm2", "%xmm3", "%xmm4", "%xmm5", "cc", "memory"
 	);
 #else
@@ -2841,7 +3151,7 @@ __attribute__ ((noinline)) void ssse3_delta8_argb(const uint8_t* col1, const uin
 	"cmp %3, %4\n\t"
 	"jb algo_ssse3_delta8_argb\n\t"
 	:
-	: "r" (col1), "r" (col2), "r" (result), "r" (count), "r" (i), "m" (*movemask)
+	: "r" (col1), "r" (col2), "r" (result), "m" (count), "r" (i), "m" (*movemask)
 	: "%eax", "%xmm0", "%xmm1", "%xmm2", "%xmm3", "%xmm4", "%xmm5", "cc", "memory"
 	);
 #else
@@ -2900,7 +3210,7 @@ __attribute__ ((noinline)) void ssse3_delta8_abgr(const uint8_t* col1, const uin
 	"cmp %3, %4\n\t"
 	"jb algo_ssse3_delta8_abgr\n\t"
 	:
-	: "r" (col1), "r" (col2), "r" (result), "r" (count), "r" (i), "m" (*movemask)
+	: "r" (col1), "r" (col2), "r" (result), "m" (count), "r" (i), "m" (*movemask)
 	: "%eax", "%xmm0", "%xmm1", "%xmm2", "%xmm3", "%xmm4", "%xmm5", "cc", "memory"
 	);
 #else
@@ -3072,7 +3382,7 @@ __attribute__ ((noinline)) void ssse3_convert_rgba_gray8(const uint8_t* col1, ui
 	"cmp %2, %3\n\t"
 	"jb algo_ssse3_convert_rgba_gray8\n\t"
 	:
-	: "r" (col1), "r" (result), "r" (count), "r" (i), "m" (*movemask)
+	: "r" (col1), "r" (result), "m" (count), "r" (i), "m" (*movemask)
 	: "%eax", "%xmm0", "%xmm1", "%xmm2", "%xmm3", "%xmm4", "%xmm5", "cc", "memory"
 	);
 #else
@@ -3113,7 +3423,7 @@ __attribute__ ((noinline)) void ssse3_convert_yuyv_gray8(const uint8_t* col1, ui
 	"cmp %2, %3\n\t"
 	"jb algo_ssse3_convert_yuyv_gray8\n\t"
 	:
-	: "r" (col1), "r" (result), "r" (count), "r" (i), "m" (*movemask1), "m" (*movemask2)
+	: "r" (col1), "r" (result), "m" (count), "r" (i), "m" (*movemask1), "m" (*movemask2)
 	: "%xmm3", "%xmm4", "cc", "memory"
 	);
 #else
diff --git a/src/zm_image.h b/src/zm_image.h
index c26db5e5d..10173c03f 100644
--- a/src/zm_image.h
+++ b/src/zm_image.h
@@ -258,6 +258,10 @@ void std_delta8_bgra(const uint8_t* col1, const uint8_t* col2, uint8_t* result,
 void std_delta8_argb(const uint8_t* col1, const uint8_t* col2, uint8_t* result, unsigned long count);
 void std_delta8_abgr(const uint8_t* col1, const uint8_t* col2, uint8_t* result, unsigned long count);
 void sse2_delta8_gray8(const uint8_t* col1, const uint8_t* col2, uint8_t* result, unsigned long count);
+void sse2_delta8_rgba(const uint8_t* col1, const uint8_t* col2, uint8_t* result, unsigned long count);
+void sse2_delta8_bgra(const uint8_t* col1, const uint8_t* col2, uint8_t* result, unsigned long count);
+void sse2_delta8_argb(const uint8_t* col1, const uint8_t* col2, uint8_t* result, unsigned long count);
+void sse2_delta8_abgr(const uint8_t* col1, const uint8_t* col2, uint8_t* result, unsigned long count);
 void ssse3_delta8_rgba(const uint8_t* col1, const uint8_t* col2, uint8_t* result, unsigned long count);
 void ssse3_delta8_bgra(const uint8_t* col1, const uint8_t* col2, uint8_t* result, unsigned long count);
 void ssse3_delta8_argb(const uint8_t* col1, const uint8_t* col2, uint8_t* result, unsigned long count);
diff --git a/src/zm_monitor.cpp b/src/zm_monitor.cpp
index ce70d7fa3..4b143c279 100644
--- a/src/zm_monitor.cpp
+++ b/src/zm_monitor.cpp
@@ -2937,6 +2937,7 @@ bool Monitor::DumpSettings( char *output, bool verbose )
     }
 #endif // ZM_HAS_V4L
     sprintf( output+strlen(output), "Colours : %d\n", camera->Colours() );
+    sprintf( output+strlen(output), "Subpixel Order : %d\n", camera->SubpixelOrder() );
     sprintf( output+strlen(output), "Event Prefix : %s\n", event_prefix );
     sprintf( output+strlen(output), "Label Format : %s\n", label_format );
     sprintf( output+strlen(output), "Label Coord : %d,%d\n", label_coord.X(), label_coord.Y() );
diff --git a/src/zm_zone.cpp b/src/zm_zone.cpp
index a2e799720..95541b116 100644
--- a/src/zm_zone.cpp
+++ b/src/zm_zone.cpp
@@ -171,28 +171,15 @@ bool Zone::CheckAlarms( const Image *delta_image )
 		hi_x = ranges[py].hi_x;
 
 		Debug( 7, "Checking line %d from %d -> %d", y, lo_x, hi_x );
-		pdiff = diff_buff + (lo_x * y);
+		pdiff = diff_buff + (diff_width * y);
 		ppoly = pg_image->Buffer( ranges[py].off_x, py );
-		// Left margin
-		if ( y < hi_y )
-		{
-			int next_lo_x = ranges[py+1].lo_x;
-			if ( next_lo_x < lo_x )
-			{
-				int lo_x_diff = lo_x-next_lo_x;
-				memset( pdiff-lo_x_diff, BLACK, lo_x_diff  );
-			}
-			else  if ( lo_x > 0 )
-				*(pdiff-1) = BLACK;
-		}
-		else  if ( lo_x > 0 )
-			*(pdiff-1) = BLACK;
+		pdiff += lo_x;
 		for ( int x = lo_x; x <= hi_x; x++, pdiff++, ppoly++ )
 		{
 			if ( *ppoly && (*pdiff > min_pixel_threshold) && (!max_pixel_threshold || (*pdiff < max_pixel_threshold)) )
 			{
 				alarm_pixels++;
-				pixel_diff_count += abs(*pdiff);
+				pixel_diff_count += *pdiff;
 				*pdiff = WHITE;
 			}
 			else
@@ -200,16 +187,6 @@ bool Zone::CheckAlarms( const Image *delta_image )
 				*pdiff = BLACK;
 			}
 		}
-		// Right margin
-		if ( y < hi_y )
-		{
-			int next_hi_x = ranges[py+1].hi_x;
-			if ( next_hi_x > hi_x )
-			{
-				//printf( "%d: Setting %d-%d = %d\n", y, hi_x, next_hi_x, next_hi_x-hi_x );
-				memset( pdiff, BLACK, next_hi_x-hi_x );
-			}
-		}
 	}
 	if ( pixel_diff_count && alarm_pixels )
 		pixel_diff = pixel_diff_count/alarm_pixels;