I'll try to talk you though it whilst on my photobucket account......
.....log in, and then click on the 'browse' button in the pale blue box under 'Upload images or Video;.
When you clock browse it will open up a screen that shows the files on your desktop/ your documents, you need to find where your photo is saved and double click on that photo.......it will bring a line of text into the white line box to the left of where you originally pressed 'browse' on Photobucket.
So then you need to click the button on the bottom right on photobucket that says 'Upload'....will take a few seconds for the website to take a copy of the picture and store it.......
Does that make sense?