Fallback for missing srcset images

We did figure out a workaround for this problem, If you are using a plugin like Regenerate Thumbnail try to deactivate first some plugins that will affect your images when you regenerate new image thumbnails like ewww image optimizer. make sure that the original image width is more than the image size you set on your media settings to avoid missing size when WordPress generates a list of thumbnails.

But still, we would like to know if there is a workaround if an image srcset URL is missing that could avoid missing images in the browser.