Drag all your image files to a new folder on your desktop.
On the NH FAIR website, click "Add Image(s)" from the "Add Media" menu, then click the "Select Images" icon near the top of the page.
Browse to the folder on your desktop that you created in step 1 and select all of the pictures in it, then click "Select" (your browser might have a button other than "Select," like "OK" or "Open" or something).
Back on NH FAIR's "Create Image" web page, click the "Save" button that's right next to the "Select Images" icon.
Wait for all the pics to load, then click the "Next" button (the "Save" button will have changed to a "Next" button).