Hey guys, I was wondering how to open an image that is already opened in photoshop cs4. I just accidentally opened it, but I dont know how anymore... how can I do this?

If you open a RAW image in Photoshop by going through ACR you cannot reopen it in ACR unless it had been opened as a Smart Object.

You have to close the current image in Photoshop, then go through the steps of opening it in ACR, and then in Photoshop.

I think if you open a raw in ACR and then close without saving, your raw is still just a "raw image" with the changes you made in ACR only. If you opened and then saved either as a psd, tiff or jpeg, then you can open that file as saved or reopen the raw file as stated above.

What file format is the file?

sorry for the late late reply, the format is in RAW (NEF). I just right click the image and put open in photoshop cs4 and of coarse since it is in raw it will open in camera raw. but when it opens in camera raw a warning sign at the top of the image (the yellow triangle with a exclamation mark) shows up and then goes off but then my bright perfect exposure image, all of a sudden becomes very dark.