Progressive image loading advantage for limited devices ?

If say an image format can be "progressively" loaded, could that then
mean that a device with a small (say 50x50) screen's UA could read just
the first few bytes of the image to render a 50x50 "thumbnail" (or even
better, a special focus area) of the image.

This would avoid having the entire image transferred on a typically
limited (thin and noisy) wireless network connection.

It would also save expensive/limited memory/computation of resizing the
image on the device.

When it comes to zooming on the image, perhaps a protocol to read the
next few bytes through the network efficiently...

Is the "progressive loading" feature what I am looking for?