How to find and remove a cached image? I have an image with url like:

http://example.com/index.php?q=sites/default/files/imagecache/node-gallery-display/123.JPG


I want to remove this image but don't know where it stored in database. 

Whenever I remove 123.JPG from the path, it is re-generated on the next GET request. 
I removed all nodes with that title from the node table but it had no effect. So I'm have no idea how to find and remove all trace of it from the database. Appreciate your help about it.
Try this:

find -name   "123.JPG" -exec rm {} \;