Your pictures will NOT be touched until you explicitly run the watermarking commands. When you are happy with the look of your watermarks, you can either
Save your watermarked pictures one by one
by clicking File/Save current image
or
Save your watermarked pictures in batch
by clicking File/Batch watermark images.
With the File/Save current image command, PhotoWatermark Professional will automatically rename your files in order to avoid conflict and give you a chance to change it before you save. You can overwrite your original picture if you wish after your confirmation.
With File/Batch watermark images, you cannot overwrite your original pictures unless you turn an option Options/Allow me to overwrite source image files (IRREVERSIBLE, you are 100% responsible) on. You will be asked to choose a destination folder which differs from the source.
A combination of resizing, converting and renaming can be specified when you perform watermarking. Watermarking command is what you pay for this program.
See also:
Features
File menu