A great way to upload images that can be used in your blog is via http://0x0.st/
A place to find images is Pexels. Good idea to choose the smallest of the image formats.
You can either download the image first then upload it using:
curl -F'file=@pexels-photo-441794.jpeg' http://0x0.st
Or by saving the link and upload it directly from the pexels site:
curl -F'url=https://images.pexels.com/photos/1237119/pexels-photo-1237119.jpeg?cs=srgb&dl=pexels-jonathan-petersson-1237119.jpg&fm=jpg&w=640&h=426' http://0x0.st
You can even host your own image server.