The ShareX image watermark tool applies a text or image watermark to one or more images. It includes a live preview and controls for placement, margin, opacity, rotation and output encoding.
Open it from Tools -> Image watermark.
The $filename token inserts the original file name into each output name. The default pattern adds _watermarked.
PNG preserves transparency and is suitable for screenshots and graphics. JPEG uses the selected quality and fills transparent areas with the chosen background color.
Use a moderate opacity so the watermark remains visible without obscuring important content. Test the smallest image in a batch: a watermark that looks balanced on a large image can dominate a lower-resolution one.