> Please add ability to enter time (hh:mm:ss) format and date too for single download

There is a "dateString" variable:
https://github.com/eight04/image-picka#filename-pattern

Does it fit your needs?

> this extension always maps back to downloads folder, instead must go to the folder I previously saved an image to just like built in firefox image download

This is a bug in Firefox. See https://github.com/eight04/image-picka/issues/15

Added in 0.7.4.

You can't. In Firefox 57+, extensions can only save the files to default download folder. Also see https://github.com/eight04/image-picka/issues/14

It doesn't grab the image from cache by the default. You can change the setting in the option page.