Image format implementation in browsers

I have created a very good lossless compretion for my website for a very specific use (about 1kb images), and I want to implement it in my website.

I know that I can decode the compression via JS, and than create a Canvas or an SVG and draw it, but I want first to know how images in different formats are implemented in browsers like Google Chrome?

Like where and in what language is it decoding the file to its pixels, and how is it showing it? (canvas/svg/different way)