thanks guys for yours answers.

l checked the file, there is the png tag...and l actually opened it with Infranview and resaved it as PNG, then visually compared ( in wordpad) both files...they are the same format.
When l try to load the first png file with qimage.load(), it fails... but it is successful if l load the second file ( the one resave with infranview).

I'm just wondering if l should save the file with a specific format ( uint, string ..), maybe Infranview can detect the format while Qimage can not, it should be a specific format...

any idea about that ?

regards,

Michael