using Aspose;
using Aspose.Pdf;
using Aspose.Pdf.InteractiveFeatures.Annotations;
using Aspose.Pdf.InteractiveFeatures;

......

Aspose.Pdf.Document doc = new Aspose.Pdf.Document(_pdfFilePath);
ImagePlacementAbsorberabs = new ImagePlacementAbsorber();

//查找图片
foreach (ImagePlacement imagePlacement in abs.ImagePlacements)
{
    XImage image = imagePlacement.Image;
}

//创建超链接
LinkAnnotation link = new LinkAnnotation(page, new Aspose.Pdf.Rectangle(imagePlacement.Rectangle.URX - 175, imagePlacement.Rectangle.URY - 90, imagePlacement.Rectangle.URX + 4, imagePlacement.Rectangle.URY + 3));
link.Color = Aspose.Pdf.Color.FromRgb(System.Drawing.Color.Empty);
//创建透明外框
link.Border = new Border(link);
link.Border.Style  = BorderStyle.Solid;
link.Border.Effect = BorderEffect.None;
link.Border.Width = 0;

link.Action = new GoToRemoteAction(@"..\..\test.pdf", 1); //连接到其他文件
//link.Action = new Aspose.Pdf.InteractiveFeatures.GoToURIAction("www.google.com"); //网址超链接 

page.Annotations.Add(link);

Aspose.pdf for c# 创建透明超链接