diff --git a/modules/imgfmt/HGPng.cpp b/modules/imgfmt/HGPng.cpp
index 271655bb..375cf3c1 100644
--- a/modules/imgfmt/HGPng.cpp
+++ b/modules/imgfmt/HGPng.cpp
@@ -147,7 +147,8 @@ HGResult HGAPI HGImgFmt_LoadPngImage(const HGChar* fileName, HGPngLoadInfo* info
 	if (NULL != image)
 	{
 		png_set_scale_16(png_ptr);
-		png_set_expand(png_ptr);
+        if (1 != info_ptr->bit_depth)
+            png_set_expand(png_ptr);
 
 		png_set_interlace_handling(png_ptr);
 		png_read_update_info(png_ptr, info_ptr);
@@ -182,7 +183,10 @@ HGResult HGAPI HGImgFmt_LoadPngImage(const HGChar* fileName, HGPngLoadInfo* info
 			}
 			else if (PNG_COLOR_TYPE_GRAY == info_ptr->color_type)
 			{
-				imgType = HGBASE_IMGTYPE_GRAY;
+                if (1 == info_ptr->bit_depth)
+                    imgType = HGBASE_IMGTYPE_BINARY;
+                else
+                    imgType = HGBASE_IMGTYPE_GRAY;
 			}
 		}
 
@@ -211,22 +215,42 @@ HGResult HGAPI HGImgFmt_LoadPngImage(const HGChar* fileName, HGPngLoadInfo* info
 
 		if (PNG_COLOR_TYPE_GRAY == info_ptr->color_type)
 		{
-			//#pragma omp parallel for
-			for (png_int_32 i = 0; i < (png_int_32)info_ptr->height; i++)
-			{
-				uint8_t* pEx = rowPointers[i];
-				uint8_t* pExEnd = pEx + info_ptr->width;
-				uint8_t* pDestEx = data + (HGSize)i * (HGSize)imgInfo.widthStep;
+            if (1 == info_ptr->bit_depth)
+            {
+                HGImageInfo imgInfo;
+                imgInfo.width = info_ptr->width;
+                imgInfo.height = info_ptr->height;
+                imgInfo.type = HGBASE_IMGTYPE_BINARY;
+                imgInfo.widthStep = info_ptr->rowbytes;
+                imgInfo.origin = HGBASE_IMGORIGIN_TOP;
 
-				while (pEx < pExEnd)
-				{
-					uint8_t v = *pEx;
-					*((uint32_t*)pDestEx) = (v & 0x000000FF) | ((v << 8) & 0x0000FF00) | ((v << 16) & 0x00FF0000) | 0xFF000000;
+                HGImage imgTmp = NULL;
+                HGBase_CreateImageWithData(buffer, &imgInfo, &imgTmp);
+                if (NULL != imgTmp)
+                {
+                    HGBase_CopyImage(imgTmp, image2);
+                    HGBase_DestroyImage(imgTmp);
+                }
+            }
+            else
+            {
+                //#pragma omp parallel for
+                for (png_int_32 i = 0; i < (png_int_32)info_ptr->height; i++)
+                {
+                    uint8_t* pEx = rowPointers[i];
+                    uint8_t* pExEnd = pEx + info_ptr->width;
+                    uint8_t* pDestEx = data + (HGSize)i * (HGSize)imgInfo.widthStep;
 
-					++pEx;
-					pDestEx += 4;
-				}
-			}
+                    while (pEx < pExEnd)
+                    {
+                        uint8_t v = *pEx;
+                        *((uint32_t*)pDestEx) = (v & 0x000000FF) | ((v << 8) & 0x0000FF00) | ((v << 16) & 0x00FF0000) | 0xFF000000;
+
+                        ++pEx;
+                        pDestEx += 4;
+                    }
+                }
+            }
 		}
 		else if (PNG_COLOR_TYPE_RGB == info_ptr->color_type)
 		{
@@ -378,14 +402,6 @@ HGResult HGAPI HGImgFmt_SavePngImage(HGImage image, const HGPngSaveInfo* info, c
 			longjmp(png_jmpbuf(png_ptr), (int)ret);
 		}
 	}
-	else if (HGBASE_IMGTYPE_BINARY == imgInfo.type)
-	{
-		HGResult ret = HGBase_CloneImage(image, HGBASE_IMGTYPE_GRAY, HGBASE_IMGORIGIN_TOP, &image2);
-		if (HGBASE_ERR_OK != ret)
-		{
-			longjmp(png_jmpbuf(png_ptr), (int)ret);
-		}
-	}
 	else
 	{
 		HGResult ret = HGBase_CloneImage(image, imgInfo.type, HGBASE_IMGORIGIN_TOP, &image2);
@@ -406,7 +422,7 @@ HGResult HGAPI HGImgFmt_SavePngImage(HGImage image, const HGPngSaveInfo* info, c
 	HGBase_GetImageData(image2, &data);
 
 	int color_type = -1;
-	if (HGBASE_IMGTYPE_GRAY == type)
+    if (HGBASE_IMGTYPE_BINARY == type || HGBASE_IMGTYPE_GRAY == type)
 		color_type = PNG_COLOR_TYPE_GRAY;
 	else if (HGBASE_IMGTYPE_RGB == type)
 		color_type = PNG_COLOR_TYPE_RGB;
@@ -414,7 +430,11 @@ HGResult HGAPI HGImgFmt_SavePngImage(HGImage image, const HGPngSaveInfo* info, c
 		color_type = PNG_COLOR_TYPE_RGB_ALPHA;
 	assert(-1 != color_type);
 
-	png_set_IHDR(png_ptr, info_ptr, width, height, 8, color_type, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+    int bpp = 8;
+    if (HGBASE_IMGTYPE_BINARY == type)
+        bpp = 1;
+
+    png_set_IHDR(png_ptr, info_ptr, width, height, bpp, color_type, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
 
 	if (NULL != info)
 	{
@@ -459,4 +479,4 @@ HGResult HGAPI HGImgFmt_SavePngImage(HGImage image, const HGPngSaveInfo* info, c
 	fclose(file);
 	file = NULL;
 	return HGBASE_ERR_OK;
-}
\ No newline at end of file
+}