Photobucket is an option, but a simpler alternative:
- Upload your picture into the Member Album.
- View your newly uploaded picture.
- See the BBCode already provided in the lower section, under the title "Linked Thumbnail". It is properly formatted and ready to copy into your post.
Below is an example, from the first picture I could find:
Click on the thumbnail to view the medium-sized image, all without leaving the comforts of Rat.Net.