QGraphicsScene not output image after add QPixmap

[debian]

Hello!
I use qt-5.5.1 x64 on linux.
For output images I use qrpaphicsscene, follow simple code

_scene->addPixmap(QPixmap::fromImage(image));

Usually I work with images in QImage::Format_RGB888, but now I have images in QImage::Format_ARGB32 and I see only black screen.
Ok, may be qgraphicsscene can't work with QImage::Format_ARGB32?
I convert image to QImage::Format_RGB888

QImage rgb = image.convertToFormat(QImage::Format_RGB888);
_scene->addPixmap(QPixmap::fromImage(rgb));

Unfortunately this not solve problem.
How can I solve this problem?
Thank you and excuse my bad english.

[SGaist]

Hi,

Might be a silly question but are you sure that the new image is valid and not null ?