Photobucket has made changes and if yours is wrong...your photos will not be the right size.
When you open Photobucket.... below is a photo of a portion of the screen that comes up..

Click the portion I have circled in red... and the following comes up..

The photo size you wish to upload should be clicked on and the dot filled in. All photos uploaded should be this 640X480 size. After making certain it is done just as this example, click on Save at the bottom of that portion.
Hope this helps. Other than this, Photobucket is having some issues.. The bulk uploader doesn't work anymore, doesn't even come up. And it freezes up easily. I feel certain it is Photobucket's problem as I don't have that issue anywhere else. Took me forever to get these two photos saved and used. Sigh!
I'm going to find a way to contact them and see what's going on.
Happy RVing!
Joella