diff --git a/mozilla/modules/libpr0n/encoders/jpeg/nsJPEGEncoder.cpp b/mozilla/modules/libpr0n/encoders/jpeg/nsJPEGEncoder.cpp
index 71c89999141..77120f53a40 100644
--- a/mozilla/modules/libpr0n/encoders/jpeg/nsJPEGEncoder.cpp
+++ b/mozilla/modules/libpr0n/encoders/jpeg/nsJPEGEncoder.cpp
@@ -266,7 +266,7 @@ NS_IMETHODIMP nsJPEGEncoder::ReadSegments(nsWriteSegmentFun aWriter, void *aClos
     aCount = maxCount;
   nsresult rv = aWriter(this, aClosure,
                         reinterpret_cast<const char*>(mImageBuffer),
-                        0, aCount, _retval);
+                        mImageBufferReadPoint, aCount, _retval);
   if (NS_SUCCEEDED(rv)) {
     NS_ASSERTION(*_retval <= aCount, "bad write count");
     mImageBufferReadPoint += *_retval;
diff --git a/mozilla/modules/libpr0n/encoders/png/nsPNGEncoder.cpp b/mozilla/modules/libpr0n/encoders/png/nsPNGEncoder.cpp
index 834017ca349..3b5cd56930f 100644
--- a/mozilla/modules/libpr0n/encoders/png/nsPNGEncoder.cpp
+++ b/mozilla/modules/libpr0n/encoders/png/nsPNGEncoder.cpp
@@ -484,7 +484,7 @@ NS_IMETHODIMP nsPNGEncoder::ReadSegments(nsWriteSegmentFun aWriter,
     aCount = maxCount;
   nsresult rv = aWriter(this, aClosure,
                         reinterpret_cast<const char*>(mImageBuffer),
-                        0, aCount, _retval);
+                        mImageBufferReadPoint, aCount, _retval);
   if (NS_SUCCEEDED(rv)) {
     NS_ASSERTION(*_retval <= aCount, "bad write count");
     mImageBufferReadPoint += *_retval;