You may have copied the line that says direct link. ?? I'm not sure. I think I usually copy the one that says HTML code unless I'm posting thumbnail images that can be enlarged.

You don't want people to be able to see family photos and stuff like that. Gardenweb doesn't have a way to edit posts so maybe it would work to just delete those photos from Photobucket that you posted so the address will be invalid.

Does someone else know how to fix it?

Thumbnails are pretty easy to do. You check the box under each photo that you want to post, then go to the bottom of the page and click on "Generate HTML and IMG Code". Click in the first box once to highlight it, then use copy and paste to put it in your post. You can post several pictures at a time that way and the page will come up quicker than it would with a lot of large photos.

I think you can keep a separate album just for garden photos but I haven't tried to figure out how to do that.

This is mostly over my head too. Wish I could help you more.