diff --git a/plugins/GSdx/GSPng.cpp b/plugins/GSdx/GSPng.cpp
index 0787a51dde..3fafcd0f4b 100644
--- a/plugins/GSdx/GSPng.cpp
+++ b/plugins/GSdx/GSPng.cpp
@@ -41,19 +41,17 @@ struct {
 
 namespace GSPng {
 
-    bool SaveFile(const string& file, Format fmt, uint8* image, uint8* row,
-        int width, int height, int pitch, int _compression,
-        bool rb_swapped = false, bool first_image = false)
+    bool SaveFile(const string& file, const Format fmt, const uint8* const image,
+        uint8* const row, const int width, const int height, const int pitch,
+        const int compression, const bool rb_swapped = false, const bool first_image = false)
     {
-        int channel_bit_depth = pixel[fmt].channel_bit_depth;
-        int bytes_per_pixel_in = pixel[fmt].bytes_per_pixel_in;
+        const int channel_bit_depth = pixel[fmt].channel_bit_depth;
+        const int bytes_per_pixel_in = pixel[fmt].bytes_per_pixel_in;
 
         const int type = first_image ? pixel[fmt].type : PNG_COLOR_TYPE_GRAY;
         const int offset = first_image ? 0 : pixel[fmt].bytes_per_pixel_out;
         const int bytes_per_pixel_out = first_image ? pixel[fmt].bytes_per_pixel_out : bytes_per_pixel_in - offset;
 
-        const int compression = (_compression < 0 || _compression > Z_BEST_COMPRESSION) ? Z_BEST_SPEED : _compression;
-
         FILE *fp = fopen(file.c_str(), "wb");
         if (fp == nullptr)
             return false;
@@ -61,7 +59,6 @@ namespace GSPng {
         png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
         png_infop info_ptr = nullptr;
 
-        bool success = false;
         try {
             if (png_ptr == nullptr)
                 throw GSDXRecoverableError();
@@ -84,24 +81,24 @@ namespace GSPng {
             if (rb_swapped && type != PNG_COLOR_TYPE_GRAY)
                 png_set_bgr(png_ptr);
 
-            for (int y = 0; y < height; ++y, image += pitch) {
+            for (int y = 0; y < height; ++y) {
                 for (int x = 0; x < width; ++x)
                     for (int i = 0; i < bytes_per_pixel_out; ++i)
-                        row[bytes_per_pixel_out * x + i] = image[bytes_per_pixel_in * x + i + offset];
+                        row[bytes_per_pixel_out * x + i] = image[y * pitch + bytes_per_pixel_in * x + i + offset];
                 png_write_row(png_ptr, row);
             }
             png_write_end(png_ptr, nullptr);
 
-            success = true;
         } catch (GSDXRecoverableError&) {
             fprintf(stderr, "Failed to write image %s\n", file.c_str());
+            return false;
         }
 
         if (png_ptr)
             png_destroy_write_struct(&png_ptr, info_ptr ? &info_ptr : nullptr);
         fclose(fp);
 
-        return success;
+        return true;
     }
 
     bool Save(GSPng::Format fmt, const string& file, uint8* image, int w, int h, int pitch, int compression, bool rb_swapped)
@@ -111,6 +108,9 @@ namespace GSPng {
 
         ASSERT(fmt >= Format::START && fmt < Format::COUNT);
 
+        if (compression < 0 || compression > Z_BEST_COMPRESSION)
+            compression = Z_BEST_SPEED;
+
         std::unique_ptr<uint8[]> row(new uint8[pixel[fmt].bytes_per_pixel_out * w]);
 
         std::string filename = root + pixel[fmt].extension[0];