The first page of the JPEG Wizard opens when you click the Use Wizard button at the bottom left corner of the dialog. It displays two pages that correspond to the tabs of the dialog.
To open the GIF Wizard:
choose File > Export > JPEG Optimizer to open the JPEG Optimizer dialog, and then click the Use Wizard button.
JPEG Wizard Page 1:
Drag the slider to set the compression value. As the saved file size decreases, so does the image quality. Click the Next button to proceed to page 2.
JPEG Wizard Page 2:
The second page displays the compressed image and its file size. To change the compression value, click the Back button to return to the previous page. Click the Finish button to open the Save As dialog, where you type a name and select a location for saving the JPEG file. The original image is not altered.