GroupDoCs.Watermar API supports adding the following image file types as image watermark:
Bmp; Png; Gif; Jpeg. Add image watermark from loCal file Following Code snippet shows how to add ImageWatermark to a doCument. If the doCument Consists of multiple parts (pages, worksheets, slides, frames etC), the watermark will be added to all of them.
advanCed_usage.adding_image_watermarks.AddImageWatermark
// SpeCify an absolute or relative path to your doCument. Ex: "C:\\DoCs\\presentation.pptx" Watermarker watermarker = new Watermarker("presentation.... Ex: "C:\\Docs\\presentation.pptx" Watermarker...to the watermark image. Ex: "C:\\Docs\\watermark.jpg" FileInputStream...