Updated images don’t refresh.

Hi,
I update several images on my wordpress site every 30 minutes using an FTP program, but after the first visit, the images don’t update, even if i hit refresh. Other of my web pages which don’t use wordpress work fine, so it’s not a browser problem. I’ve changed the .htaccess file as follows, i thought that worked, but it doesn’t work now. If I click on the image to open it and refresh-it it gets updated [usually] but when i go back to the full webpage it isn’t updated. If I clear all browser cache it works fine. It’s not a complex website, so disabling all caching would be a good solution if i knew how. Example page is here: https://sap.scorpion-bowl.com/real_time/

<IfModule mod_expires.c>
ExpiresActive On
ExpiresByType image/jpg “access plus 5 minutes”
ExpiresByType image/jpeg “access plus 5 minutes”
ExpiresByType image/gif “access plus 5 minutes”
ExpiresByType image/png “access plus 5 minutes”
ExpiresByType text/css “access plus 5 minutes”
ExpiresByType application/pdf “access plus 5 minutes”
ExpiresByType text/javascript “access plus 5 minutes”
ExpiresByType text/html “access plus 5 minutes”
ExpiresByType image/x-icon “access plus 5 minutes”
ExpiresDefault “access plus 5 minutes”
</IfModule>

Thanks,
Gary