File Types options
Click check boxes on this tab to specify the file types that Picasa will track and display.Note:
On its first scan (see page 12), Picasa skips GIF (Graphics Interchange Format) and PNG (Portable Network Graphics) files. Both file formats are used for Web graphics. Of the two, GIF files are more common, though. To instruct Picasa to track these file types, click their check boxes.