Pew Research of 40 countries around the globe found that in only three—Bangladesh, Indonesia and Pakistan—did a majority have a favourable view of Iran.
Notice particularly that none of those countries is in the Middle East. Iran's popularity has been declining steadily throughout the area over the past decade, including surprisingly in the Palestinian Territories. Also surprisingly, in Turkey, Tunisia, Jordan and Egypt, the new president, Hassan Rouhani, is even less popular than his predecessor, the controversial Mahmoud Ahmadinejad.
Not so surprisingly, the survey revealed religious divisions. For example, large majorities of Lebanese Shias held a favourable view of Iran and its president while most Sunnis and Christians held an unfavourable view.
Among the nations engaged in nuclear talks with Tehran (the five permanent members of the UN Security Council and Germany), public attitudes are largely critical of Iran. Even most Russians, although somewhat more divided, are negative toward the country.
If the U.S. and Israel are in a PR contest with Iran, they are winning hands down. Even if the Iranians don't care much for world opinion, they do their negotiating position no favour when almost the entire international community looks unfavourably on them. Their image needs a lot of polishing. On the other hand, it could just be their behaviour.