You can't use HTML directly in posts. That's why your embed codes aren't working.
When you're composing a post, you have to click the 'Insert Image' icon above the text window, and it will prompt you for the URL of the off-site image. Once you paste that URL in and click Okay, it will be put in your post.
I fixed the image links in your thread for you.
“I think that when the lies are all told and forgot the truth will be there yet. It dont move about from place to place and it dont change from time to time. You cant corrupt it any more than you can salt salt.” - Cormac McCarthy