Ok, so here's a screenshot of your first picture, opened. Take a look at the bottom right corner of the black area - do you see a Star, Right curved arrow, Down arrow on line, and Two little diagonal arrows? If so, then you click on the Right curved arrow, which opens a box where the first time (within what length of time I'm not sure) you will need to click on Embed. Once you do that you can click the down arrow for choosing a size. Go with a medium size. Usually once you do that the size is there for the rest of the pics you go to post. Once you do that, you can copy the line of data in the narrow box above that. Then go to the post and right click Paste. If you're going to post more than one picture select and cut the data at the end of it, after the < a >. If that doesn't seem clear, I'll have to send the info in email - it won't let me post how it looks here. So annoying!
Preview and hopefully you'll see pics! I hope this helps. It's gets easier and easier until you don't really think about it when you do it! :>)