The issue is that this forum does not store (host) photos, they must be hosted somewhere else. I use my web site, so it's very easy. Flickr does seem to complicate things, but it's not that hard as you can see:
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The key is to grab the proper link. Here's what I did:
Went to your Flickr page and clicked on an image. Then I clicked the Share Photo icon (the arrow pointing to the right, next to the star at the bottom right). On the Share Image dialog, I clicked Embed. Then I opened up Notepad (can use any text editor) and pasted the link. Then I copied the URL of the image. You need to find the link that immediately follows src=. Everything inside the quotes needs to be copied. The link for the photo above is https://c1.staticflickr.com/3/2867/33239012695_caf4e9cf6c_c.jpg.
One issue. That link points to the original photo, it is not resized at all, so for large photos like the one I posted, you need to add a width to the image tag. Using 800 as the width is a good size. You can leave the height blank, the browser will automatically scale the height.
So the image tag would look like this (just use the correct braces, I used curly braces so the forum wouldn't display a photo): {img}https://c1.staticflickr.com/4/3930/32424605513_67437e47c0_k.jpg width=640{/img}
-Michael
Moderator edit to re-size picture to forum limit of 640px maximum width.