Too dark images in sequencer since 2.64

Hi,

I rendered some scene in 2.63 and wanted to switch to 2.64.
But in the sequencer of 2.64 the imported images are displayed darker than the originals. The output video is darker too.

Did I something wrong? Is it a special feature in 2.64? It’s happening on Windows 32bit and Ubuntu 64bit.

Thx

Andy