>> It seems that when I use WAListener, the server sent the image file of the size
>> of 16135 byte, but original file size is 10819 byte, and this might be the source
>> of the problem. I cannot open wrong sized file even though I cut the size of the
>> file to the original one.
> 
> WAListener should not do any encoding at all so images should work.
> But then again we don't know what code you changed so we can't really
> help you. It would help if you send us the image so we can test.

It's likely that your images' bytes are being UTF-8 encoded.  If the 
bytes are uniform, you can expect a 50% increase in size (the low 128 
bytes are passed as they are, the high 128 bytes are expanded to two 
bytes; (128+128*2)/256 = 1.5) and that's what you are seeing.

Paolo