When I drop a picture in a WAP Web page, the entire WAP page is replaced by the full-sized picture. Why?

When you use Drag&Drop Tool it will happen like this if you drop over the address bar of your internet browser.
To avoid this be careful to drop over the folder icon which will turn green, saying 'Drop Here'. Once you have dropped a dialog window will open and you shall click 'Upload' to start the process. As soon as the picture is uploaded the dialog window will close and will return you to your album.