BLOB as out parameter with Stored Procedure

Hi

I am retrieving an image from database using BLOB as out parameter to a stored procedure .
I am using VB with oracle.
.

When I am retrieving image upto size 70KB
the image bytes are retrieved correctly and written to a temporary file and the image is shown in picture box.

But if the size exceeds 70KB it gives an error. The BLOB out parameter does not return all the data, it return some 23KB odd
bytes which do not form complete image.
Why it is happening?

I tried to retrieve the same image as a field in recordset using GetChunck() method.
It returns the complete image in one shot or in small parts correctly.

Parameter object does not have any GetChunck() method to retrieve the data in small parts.

So how it can be? Is there any limitation with Parameter object.

Thanks