alt. + letter instead of mouse clicks

[nelsh]

Inserting images into a document (email) I have found it is much easier to
activate the dialog windows alt key and the underlined letter. Sometimes
arrow or enter keys.
Except when I get to insert image file dialog window. The window displays
thumbnails, which is most helpful. Except for, I am at a loss as to how
navigate in that window and indicate selection, save with the mouse.
What am I missing?

 

[Mark L. Ferguson]

The tab, shift tab, and ctrl tab keys move the focus in windows.