Whether it is Android or iOS, to programatically convert an image from colored to grayscale requires a handsome amount of coding - unless you are using Sulata.Net's APIs.
Sulata.Net provides a sufficient number of APIs to extend you ease in programming. All you need to do is follow the steps below.
Let us suppose you want to convert the following picture from colored to grayscale.
You just need to send an API request to a URL like this.
You will get a JSON response like this.
The above JSON response says that there is no error and the converted to grayscale picture is available at output URL.
With this little line of code, you can make quite a lot of applications, like Picture Effects.
There are many other, ready-to-use APIs available at www.sulata.net. You can just grab the idea and launch your own app or use it for any of your requirements.