Problem saving JPG image

[avis_phoenix]

I had a Qimage, when I tried saving this image in JPG in console show this Message:

"QJpegHandler: Unable to write image in format 7"

Use this command to save the image:

image.save(filename,"JPG");

image.save(filename,"JPG");

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I use Qt 4.5.2 in Ubuntu 8.04 maybe I need some library