Serve images from a new directory, with, or without, a redirect. Depending on SEO needs, you may be better served by rewriting requests to preserve existing URLs to images or it may be best to redirect to the new image location; many factors involved.
Refer also to: Virtual Host Config or .htaccess?
Serve From New Directory Without Redirect
To allow requests to images in a directory to be served from another directory without a redirect, add the following rule to .htaccess:
RewriteRule ^oldimages/([^/]+)\.(jpg|jpeg|gif|png))$ /newimages/$1 [L]
This would cause requests to /oldimages/image.png (or .jpg, .jpeg, .gif) to be rewritten as /newimages/image.png (or .jpg, .jpeg, .gif) . The original URL can continued to be used without the need for redirect.
Serve From New Directory Via Redirect
To redirect requests to images in a directory to be served from another directory by way of a redirect, add the following rule to .htaccess:
RewriteRule ^oldimages/([^/]+)\.(jpg|jpeg|gif|png))$ /newimages/$1 [R=301,L]
This would cause requests to /oldimages/image.png (or .jpg, .jpeg, .gif) to be redirected to /newimages/image.png (or .jpg, .jpeg, .gif) . If used for the purposes of restructuring a site’s assets, the redirect should be Permanent (301).