The main program window of uMark is mainly divided in two parts. The images and watermarks area on left and preview are on the right.

On the left you can add images for watermarking, add different types of watermarks like text, image or previously saved watermarks and start the watermarking process.

On the right you can view the preview of the image on which you are applying the watermark in various sizes including full screen. You can zoom in, zoom out, view the image in full size or scaled to fit the viewing area.