I think after recent updates you can no longer direct link from photobucket, It will just show a link to your image, not the actual image. You can upload a file from your computer and have the image show in your thread.
Just keep the files size under 150KB here is an example: this is 139kb and 1023x685 this is hosted on photobucket
It is the file size that is the limit here, like stated above keep the file size under 150kb. It took me searching for one that was over 800x600 seeing I normally resize to that, so sorry for a poor pic for an example.
in photobucket go to edit then just click "save as" at the bottom of the pop up window there is a slider bar and the file size to the right. adjust the slider bar till its just under 150kb and your good to save it. then just copy and past the link from the untitled pic...
direct link still works....this is my test photo from photobucket....just click on the IMC Code and paste it here....pic should show. No reducing pic size needed. If your pic is large tho, sometimes you have to arrow over to see the entire pic so it might be easier to still reduce the size first before linking.