Add Expires Headers for Specific Images - .htaccess

Question

All of the expires headers articles I've looked at give more or less the following solution:
ExpiresByType image/gif A2592000
ExpiresByType image/png A2592000
ExpiresByType image/jpg A2592000
ExpiresByType image/jpeg A2592000
But it doesn't make sense to me because I know which of my images are going to change and which aren't, so I want to be able to add specific expiration dates to specific image files. How would I go about this?

Answer 1

You can use a FilesMatch, eg.
<FilesMatch "\.(js|css)$">
ExpiresActive on
ExpiresDefault "access plus 1 month"
</FilesMatch>
Or for some specific files:
<FilesMatch "^(example.js|sample.css)$">
ExpiresActive on
ExpiresDefault "access plus 1 month"
</FilesMatch>

Answer 2

Note that using ExpiresDefault for specific files will not work if you already used ExpiresByType. You need to use ExpiresByType again.
So this will NOT work (service-worker.js would still have +1 year expiry):
<IfModule mod_expires.c>
ExpiresActive on
ExpiresDefault "access plus 1 month"
ExpiresByType application/javascript "access plus 1 year"
<FilesMatch "^(service-worker.js)$">
ExpiresDefault "access plus 0 seconds"
</FilesMatch>
</IfModule>
But this will work (service-worker.js will have +0 seconds expiry):
<IfModule mod_expires.c>
ExpiresActive on
ExpiresDefault "access plus 1 month"
ExpiresByType application/javascript "access plus 1 year"
<FilesMatch "^(service-worker.js)$">
ExpiresByType application/javascript "access plus 0 seconds"
</FilesMatch>
</IfModule>
You might also use Header unset Expires. This would remove Expires header no matter what was set above it. You should also modify (or remove) Cache-Control header. It seems that mod_expires sets both.
<FilesMatch "^(service-worker.js)$">
Header unset Expires
Header set Cache-Control "max-age=0"
</FilesMatch>