On the bottom of each photo on Photobucket there are three ways to copy the image to someplace, and the one you'll want to use is the last one. It starts with
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Put your cursor on it and click to copy it. Sometimes I have to click on it and then go up to the toolbar, on the top of the screen, and click "copy" out of the "edit" menu there. Whatever -- once the [img] has been clicked on so you can copy it -- go to the Forum post you're working on, put your cursor where you want the photo to be, and click "paste". You'll get that long line of goofy-looking identity-of-the-photo stuff pasted right into the post. You won't see the picture then, but once you're done with the entire post and click "Post" -- the resulting post will be your text and the photos in full living color.
What you're doing is embedding a link to the photobucket image right in the middle of your post. It not only allows you to avoid having the "filename already used" message given to you, but with the Photobucket site you can have picture files as big as you might want. Better still, it takes up almost no room on the landracing.com site, helping keep things small (and therefore cheap) on the server.
There are other "photo" sites, like Flikr (or some such spelling) and probably others. Photobucket gives you plenty of space for all the photos you're likely to want to store - - free. I pay $25/year and get way more space, but I post so many - especially during events - that I use up all of the free space pretty early in the year.