Upoading the image to a public web host is a MUST.

The picture I used itself already is on a public web host so you don't have to upload it.

It is a picture from the Park's web, isn't it? So, for this specific picture, no, you do not need upload it again. You could just replace the "src" with its own link, the one you gave.

I save it as a personal file to demo how to post the pictures that you take and upload to your computer. Try a few with your own shooting and let us know how good/bad they are.

Do not upload your picture directly from your own computer drive. They are only visible to you( and hackers if they are watching ).

Take care, Sir.