Image Sizes and Missing Filenames Display

I’ve always been vexed by the multiple resizing of images in WP and having no easy method of finding out what the filenames are (that I know of).

THE NORM
Normally, WP creates different sizes and appends a width by height to each thumb, med, and lrg version in addition to the source file.

INVISIBLE
BUT, there’s no way from the Admin area to determine what those filenames are. Since they change based on the size of the source image, it’s a black hole in the media management of WP for those who can’t or don’t want to view the files via FTP (and who should have to anyhow, power user or not?).

It seems obvious that the Media Library should display this info for each image, though that would not be very helpful without an image path copy or insertion method.

LAY USERS
As usual, this problem is compounded for lay people (i.e., my clients) who don’t care about filenames and just want to be able to pick the right sized image for the job at hand.

PLUGIN OR FUNCTION SOLUTION?
Does anyone know of a plugin that can peer into the image files uploaded and display what all of the filenames are that WP creates? Maybe there’s a short code method that makes it easy to add images based on a thumb, med, or lrg designation?

BEYOND POSTS
Ideally, this display and injection method can be independent of the Posts and Pages interface since people might want to inject or display images in text widgets too.

THANKS
Any help is much appreciated as this has always been a problem for me and I imagine others too.