David,
Those are JPEG compression artifacts. The file size of your
original is only 117 KB. It should be about 1117 KB out of the
camera. That means it has been compressed to about one tenth of its
original size. I would have several questions.
Do those lines appear when you first upload the image out of your
camera? Do you save them as JPEGs after editing, and if so what
setting is your editor set at? Are you saving, then opening to work
on and resaving several times? When you compress them to post on
pbase, what compression setting are you using.
It is very common to see these artifacts on pbase; lost of people
over compress to speed up the upload.
I downloaded your original and loaded it into BreezBrowser to get
at your EXIF data and the histogram is wild. There is a hockey sock
(Canadian term) of noise in that picture. Take a good look at the
road on the original, the JPEG compression has pixellated the image
and made it noisy.
If you are going to shoot in Large/Fine, you need to save at
minimum compression (best quality). Better yet save as TIF to work
on and save, and convert back to jpeg to email or post.
Cheers
--
Happy Snapping
Don McVee
http://www.pbase.com/mcveed