Welcome Jeff!!
That thread would be a good one to test posting but it’s pretty simple. I highly recommend Imgur for your photos and just incase you’re not aware, you want the share codes which give you the root image. If you simply copy & paste the Imgur page it will only give you a link to the page. The actual share code gives you the root image code (see below)
As far as image size goes, if your image is super small such as the meme at the bottom of my post that’s typically fine. If your image is larger than about 250 pixels wide then it’s highly recommended you use the width variation. Images like the large screenshots below I’ve used 100% and for memes or random stuff 40-80% is usually good. Without using the resizing option mobile users encounter a ton of annoying multi page wide photos



