How do you have it set up?
Before uploading your images to your Photobucket account, choose either a
display or file size that is equal to or larger than that of your images. You
can do this by clicking on the 'Uploading Options' link in your upload panel
and then on the radio button next to your preferred size. If an option is
greyed out, this means the option is not available for your Photobucket
account type. Selecting a size larger than your images will prevent further
resizing upon upload and help expedite the upload process. To make the changes
permanent, you must upload at least one image from the upload panel. This is
important for Pro users using FTP or anyone using the Windows XP Publisher. If
you choose to use the file size options, the file size of the original image
will take precedence over the the display size and any display size is
accepted as long as the file size is less than your choice in the 'Uploading
Options'.