Linux QT - how can I transform qimage to qfile

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file

QT

image

HTTP

hi i`m making program taking my picture and uploading at http SERVER.
now i already successed to make uploading picture by using Networkmanager.post function.
but i have some problem.

post function is needed request and QDeviceIO type object.
so if i upload image, i have to upload by QFile or QBuffer.

if i read QFile from local directory, i could upload file to HTTP SERVER.
but, i don`t want make Image file on local directory.

i need to send Image from QImage ( not from File on local Directory )

anyone know how can i upload QImage to HTTP SERVER without making ImageFile ?

What I have tried:

QByteArray bytes;
QBuffer* buffer = new QBuffer(&bytes);
buffer->open(QIODevice::ReadWrite);
(QImage)file->save(buffer,"PNG");

but when i tried upload, it coudln`t be uploaded.

if i upload by using this code ( from local Directory )

QFile* buffer = new QFile("test.png");
uploading was successed.