Hi.

There is no easy way after deleting an article. Before deleting you should check article settings and find there path to image.

Tip. Do not use Helix blog Featured Image option. Use standart Joomla tools (images and links tab). When adding images to the site, always choose your own path to the folder. Do not allow the system to create a default path like year/month / day/.

If I may....

Even if you deleted article, it still should be in TRASH. So you can check it, and delete image.

OR

download all images on your laptop nad browse folders one by one.

Is that possible Developer could add an optional server path for Blog Image uploading instead of the default month/day path ? That will be very helpful