delete unused images

[omid_firoznia]

Hi
 as i see in files usually there is 4 same images in upload folder for each ad and as i see just 2 of theme in use for example ((  1.jpg  - 1_original.jpg   -  1_preview.jpg   -  1_thumbnail.jpg ))

and just these two in use ((  1.jpg   -   1_thumbnail.jpg ))  !!  if im wrong please correct me?

and if im right how to delete these unused images? because they take a lot of places of host!!
i mean is there any plugin to delete these or you suggest that i do not delete these images?

[Web-Media]

Hy
1_original has small usage across themes and is the largest one
 Just uncheck checkbox named  ' keep original image '  in admin panel and future uploads do not upload original
1_preview  has some usage by different themes. Keep it

[omid_firoznia]

thanks a lot.

what about the images that uploaded before can i delete them from my host ? (i mean i_original)

[Web-Media]

Hy. backup images just in case