We just released a new feature which allows you to set the ouput format, quality and DPI before you start to process.
You can find the "Output settings" text link below the "Start to Process" button.
Click it and you will see the settings.
For example, if you want to print out your image after enlargement, you can set the output DPI to 300.
You can also select the output format, PNG or JPG.
Note: If you select to use the "Remove background" feature, the output format can be only PNG.