I downloaded it to have a better look - isn't your original is a bit big and 300 dpi ! - or am I wrong?
You might not have noticed this from afew:
If your original photo is, say, 800 x 600 (top limit for free accounts on Photobucket), and you post it with width="400", you'll get a smaller display but the browser still has to load all the bytes of the original, and that may be quite a lot.
We won't be beating anyone up who gets it wrong at first and we appreciate all contributions. Ad astra per aspera