IMxDocument objMxDocument=null;
IMap objMap=null;
IRasterWorkspace objRasterWorkspace = null;
IRasterLayer objRasterLayer = null;
IRasterDataset objRasterDataset = null;
IDataset objDataset = null;
IWorkspace objWorkspace = null;
IWorkspaceFactory objWorkspaceFactory = null;
objWorkspaceFactory = new RasterWorkspaceFactoryClass();
objWorkspace = objWorkspaceFactory.OpenFromFile(strFile, 0) as IWorkspace;
objRasterWorkspace = objWorkspace as IRasterWorkspace;
objRasterDataset = objRasterWorkspace.OpenRasterDataset(strSplit[5].ToString());
objRasterLayer = new RasterLayerClass();
objRasterLayer.CreateFromDataset(objRasterDataset);
objMxDocument = AttachementTool.m_application.Document as IMxDocument;
objMap = objMxDocument.FocusMap;
objMxDocument.AddLayer(objRasterLayer);
objMxDocument.ActiveView.Refresh();Please follow the below code for Add a JPEG image to ArcMap.