I left it as it is because the [capturemath gem] (https://github.com/quipper/capturemath) converts this data and returns binary png. that can be persisted on s3 as image files. Just spoke to @mvarnagiris about consumption of PNG and he mentioned that it would be preferable to have binary PNG on Android as opposed to base64 encoded version. 

The `'data:image/png;base64,'` in that case would anyways have to be stripped before binary decoding of Base64 string.