"Scan" a local directory for files with javascript

[admin]

If it is possible to Preload images and it is
and
if it is possible to call on those as a source for an image object and it is
and
if we can check to see if the image loaded from that call and we can

Aren't we scanning a folder for files with javascript?
Is that not what we are doing?

if not, what are we doing?