Recommendations for Learning More About Responsive Images?

I am looking for help understanding Responsive Images and how to work with them.

I run the website RinkAtlas, a directory of 4,700 North American hockey arenas.

We also have almost 1,800 published photos of those arenas, ranging in size from 11 Kilobytes to 13 Megabytes in size. I know that displaying photos with sizes in excess of 5 Megabytes is inefficient and unnecessary for our web application.

I’ve spoken to a few friends who are also web developers and mobile app developers, but none of them have been too involved in building a Responsive Image management function into their apps.

I’ve tried looking for guidance at other developer resource sites such as Stack Overflow. One of the big issues with question/answer sites like that is that open-ended questions are frowned upon; In my experience, you have to have a concise, well-phrased question in mind in order to get any value out of it.

I started searching here on Dev.to, and a bit of a breakthrough came when I searched for “Image Management”.

I found a post JPEG, GIF, PNG OR SVG - Which should You use?, which referred to a course on “Responsive Images”. Before I started searching, I didn’t even know what term to use to characterize the solution I was seeking.

So, I started searching the web for “responsive images course”.

I found:

• a Responsive Images course at Udacity,
• a Responsive Images course at Lynda.com / LinkedIn Learning,
• a Responsive Design course at Coursera, and
• a Responsive Images course at Treehouse.

Have you taken any of these courses and gotten the knowledge you needed?

Have you taken more than one of these courses and found one better than the other, or reviewed any of these courses for your corporate training needs?

Do you have any other suggestions?