1. By default, images are saved in Microsoft Internet Explorer as bitmap images (.bmp) only. This behavior may be experenced even when an image being saved uses a different format (such as .gif or .jpeg). For example, right-clicking an image on a Web page and then clicking Save Picture As, the file name that appears in the File name box is Untitled and the file type that appears in the Save as type box is Bitmap (*.bmp), [Q810978]:

a. If a damaged program file (for example, an ActiveX or Java object) is downloaded to the SystemRoot\Downloaded Program Files folder.
==and/or==
b. The contents of the Temporary Internet Files folder have not been purged recently, (Tools, Internet Options, and in the section titled Temporary Internet files, Delete Files...).

2. When the Save Picture As option for a graphics file through Microsoft Internet Explorer is used, you may only be allowed to save the file as a BMP file even if the file is in another format -- for example, GIF or JPEG because "IE Does Not Save Graphics Files in the Proper Format if Username:Password Is Part of the URL (Q260650)", and for other reasons explained in this article.

Bill Gaston