I am working on SEO on a multiregional site and we have a decent naming convention which is in English as the primary language of the site. The ideal would be to serve file names in regional languages but I also need to think about content editors and managers who might be searching for files and not speak the local language, even though we got a good folder structure but still. There is always ALT text that tells both Google and a user what is on the image. Besides, I've seen on multinational sites that they also don't use regional languages or even have a poor naming convention (not that I'm aiming for that) and still doing pretty well with SEO.
I heard there is a PHP function that can serve one image and change the file name based on a regional language, so I'm wondering how do you do that and does anyone have any source I can read about it?
In this case, do we still need to have translated text for the files to be able to serve them automatically or does it pull down the translation from google translate or how the translation works?