As shown below, the bridge in that photo sure looks a lot like the Roberto Clemente Bridge and/or Andy Warhol Bridge in Pittsburgh, and many of the buildings in the background appear all-too-similar as well (as demonstrated most clearly by the BNY Mellon Center just to the left of center at the top of each photo).
And here's another viewpoint, courtesy of Joe Marruchella of Austin, Texas:
(Joe Marrachulle: http://joerunfordom.wordpress.com/)
Weiner's campaign could not immediately be reached for comment.
Mistakes in background images aren't that uncommon, with campaigns or their consultants pulling stock art or footage that sometimes comes from the wrong locale. For example, a Mitt Romney ad on the Ohio auto industry featured footage from Oklahoma, and a Colorado Senate ad in 2008 used footage of Alaska's Mount McKinley rather than Colorado's Pikes Peak.
The bottom of the website says it is "powered by NGP VAN" -- a campaign technology company based in Massachusetts and Washington, D.C.
Update 4:31 p.m.: Weiner's website now features a different background of (what appears to be) several photographs of New York City sights.
Update 5:13 p.m.: NGP VAN is taking the blame for the miscue. A statement from John Brougher, the firm's vice president of marketing and nonprofit outreach:
"This is our fault. NGP VAN acknowledges that the image of the wrong skyline on the placeholder page for the Weiner campaign was our honest mistake, and not that of the Weiner campaign. Our designer got the image from a set of images that included New York City images, but obviously this image was not of New York City, as the Weiner campaign had requested. With the image behind a strong blue background, our team did not catch this mistake. The offending image has been replaced, and the placeholder page now uses a New York City image, as will the full website when it launches."