I would have loved to be able to download a small, web optimized version of the images in envato elements so I don’t have to scale them down from 20000px to 1200px and the resolution from 3000dpi to 72 
I don’t think it’s possible. You can use third party apps to resize them ( e.g Photoshop ) automatically.
Envato doesn’t allow to resize image you have to use other software for that and there are also some websites to compress the image size but am worried that clarity may compromise.