Many point to images as being the root cause and to a certain degree they are, but images do not block rendering. Images can and should be optimized, which reduces the overall page size.
Optimizing image file sizes can reduce the overall payload size by an average of 25%. If the page is 1 MB, 25% equals a 250 KB payload reduction.
Responsive images should also be used. This is where you use the srcset image and sizes attributes, or the picture element to reference images that are sized appropriately for the display:
<img srcset="img/pwa-tickets-logo-1158x559.png 1158w, img/pwa-tickets-logo-700x338.png 700w, img/pwa-tickets-logo-570x276.png 570w, img/pwa-tickets-logo-533x258.png 533w, img/pwa-tickets-logo-460x223.png 460w, img/pwa-tickets-logo-320x155.png 320w" src="img/pwa-tickets-logo-1158x559...