Ways to reduce image size without reducing quality

I am building a WordPress website, and the website runs perfectly, but the images don’t load. I’ve reduced the image sizes from megabytes to kilobytes, but the images still do not load.

I used GIMP and www.iloveimg.com and a few other free online compressing tools, but they either do not reduce the images at all, or drastically reduce the quality.

Are there other free tools I can use to reduce these sizes but keep quality?

You could go online, and search up on google “how to reduce an image size without reducing the quality of an image”. If the websites that you mentioend aren’t working than I don’t know what.

What makes you think it is the size of the images that are causing them not to load?

There is always a tradeoff between size and quality, it is unavoidable. But if the images can not be compressed more then all you can really do is lower the resolution. Also, make sure they are in the correct format.