Though Instagram is getting some negative feedback because of its recently launched app for the Android platform, leading some Apple users to criticize the photo-sharing app, investors aren’t fazed one bit.

AllThingsD reports that Instagram is near closing a $50 million Series B funding led by Sequoia Capital with the possible participation of DST.  If this round of funding closes, it would put Instagram’s valuation at $500 million.

Instagram had more than 30 million Apple users as of last week, and that number quickly increased by a million just 12 hours after the Android version launched.  Though anyone would be impressed with Instagram’s user base, we can’t deny the fact that it doesn’t really generate revenue, so putting a $500 million on it is considered absurd by some critics.

CEO Kevin Systrom declined to comment on the funding.  No news yet as to where the alleged new funding would be used.

Instagram is a photo sharing application for iOS and Android devices that allows users to take a photo, apply a digital filter, then share it on a variety of social networking services, including Instagram’s own.  The app was developed in San Francisco by Systrom and Mike Krieger and launched on iTunes in October 6, 2010.   It was named Apple’s “App of the Year” for 2011.

In February 2011, Instagram raised a $7 million Series A round of funding led by Benchmark Capital with the participation of Silicon Valley investors such as Twitter founder Jack Dorsey and Quora co-founder Adam D’Angelo.  Back then, Instagram only had four people running the company.  In just a year, their workforce tripled as they now have 13 employees.