When tech bloggers discovered an icon for the popular mobile game Angry Birds in a Windows Phone 7 promotional image, it seemed like confirmation that the game is coming to Microsoft’s smartphones, but the developers behind Angry Birds tweeted a denial of any commitment to the platform.

Microsoft reps then sent a note to TechFlash admitting that the image was a mistake. “It appears information was mistakenly posted to Microsoft’s website, and has been removed,” the statement said.

Microsoft will need developers like Angry Birds developer Rovio to make Windows Phone 7 attractive to iPhone () or Android () users who are accustomed to having a large selection of high-quality apps. Rovio said it was not thrilled because, “We don’t like others using our [intellectual property] without asking.”

However, we don’t want to overstate the blunder. We expect that Microsoft and Rovio will both move on and work together if the market for a Windows Phone 7 version of Angry Birds is there and waiting to pay for it.

Rovio even admitted as much in later tweets: “Nothing to do with if we do or don’t, it’s just that we decide that for ourselves … We could do a WP7 version of Angry Birds, not the issue. We have not agreed to do that (yet). Will support all relevant platforms.”

Angry Birds is a standard-setting iPhone game that also appears on Android, webOS and some Nokia phones. It has sold at least 6.5 million copies to date, so it’s a perfect example of an app store success story — a story Microsoft would like to see told on the Windows Phone 7 platform, too.