This should not have a significant impact on the loading of images. However, it can be optimised to exclude the /images
directory from being processed.
For example:
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule !^images/ index.html [L]
The QSA
flag was not required.
OR, exclude all requests that look like they already have a file extension, which should naturally include all your images, JS, CSS and any other static resources. However, this does mean that your page URLs cannot contain what looks like a file extension.
For example:
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule !\.\w{2,4}$ index.html [L]