Reposted with new pics...
Flickr is a little different to use then Photobucket. The code to use for posting photos isn't shown upfront, but it is there!
When viewing the image you want to post, click on the button "All Sizes". Note: sometimes this is only viewable to the owner of the photo depending on their privacy settings.
The "All Sizes" page shows up to 5 different resized images of your original image. (depending on what image size you uploaded) You click on the size you want to use. Keeping in mind not to post image sizes over 800 x 600 on the forums.
Then below image you chose to use, at the very bottom of the page where you could almost miss it.. There is the lovely code you want
"Grab this photo's URL" is the one you want.
Copy it and then paste it into the post, remembering to put it inside the image tags.
[img] your url to image here [/img]
And then there is no stopping you posting millions of photos of your Aquariums, Fish and other furbabies :(