To post Youtube videos with a reasonable size, insert "width" parameter. I find width=600 to be fairly easy on the eye.
Also, for quick image posting that I do not intend to keep for long term (like family or trip photos), recently, I've been using "imgur.com" and their app on the phone. Super easy to upload. I never post to "Community", which makes it public, but I just click on Hidden to get a link to the post. Anyone with the link can see the post with your images. If just to get the image to embed in a post, right click on the image and "save image address".
Here is an example of the quick post I made to illustrate:
https://imgur.com/a/Mq95YfK
