all you have to do with EP ,is too append Images_1/ to image name
images_1/myimage.jpg
you are currently using EP by only adding image name , no folder , or subfolder . ie : myimage.jpg ,and ZC uses the configure.php entry ( "images/") to create the path to image. the extra sub name should point zencart to correct location of your new images as long as your sub folders are contained within Images folder . new subfolder will not alter current operation of your zc, because correct path to your 24k images are in db ..
however, you may still have problem with FTP , due to the fact that all your images are in images folder , but subfolder might solve problem that you mentioned .. ( not uploading ) .



