Cari tanda tangan Image di file Ppt

        
// Set up input Ppt file
string filePath = "input.ppt";

// Instantiate Signature for input file
using (GroupDocs.Signature.Signature signature = new GroupDocs.Signature.Signature(filePath))
{
        //Create search options
        ImageSearchOptions options = new ImageSearchOptions()
        {
            // set minimum size if needed
            MinContentSize = 100,
            // set maximum image size if needed
            MaxContentSize = 2000,                    
            // return  Image images for processing
            ReturnContent = true,
            // set up type of returned  Image images
            ReturnContentType = FileType.PNG                                 
        };

        // search for Image signatures in Ppt document
        List<ImageSignature> signatures = signature.Search<ImageSignature>(options);

        // process signatures which were found                
        foreach (ImageSignature item in signatures)
        {
            //...
        }
}