You can edit JPG files in Adobe Camera Raw

You can edit JPG files in Adobe Camera Raw, originally uploaded by vanessapr.

In Adobe Photoshop CS3 they included the ability to open jpg photos in Adobe Camera Raw(ACR). You can either edit the preferences so that Photoshop CS3 opens up ALL jpg files in ACR or you can hold down the Alt key when opening a file from Photoshop CS3's Open>File feature.

The main difference is that the white balance doesn't show different colour temperature settings (eg. Cloudy, Shade, Tungsten etc) but has only 'As Shot', Auto and Custom. The photo is then opened in Photoshop CS3 as a 'Smart object' which provides a 'lossless' file you can apply 'Smart filters' and 'Adjustment layers' to.