How to publish images with metadata:
Try Googling any social media site/app you use to see if they offer creator tools or advice for succeeding on the platform. These companies want you to do well on their platforms, so they will publish tips!
Page headers and image titles (alt text) help to make your website more accessible to people using a screen reader. You can make other adjustments to improve the accesibility of your website, for example some people will be navigating around your website using the Tab button instead of a mouse/trackpad. You can run an accessibility check on your website!