It would be great if you implement PDF to Bitmap conversion for Android 4.x.x because it lacks built-in API.
Thanks for your inquriy. Aspose.Pdf for Android supports the PDF to BMP conversion but I am afraid it is malfunctioning at the moment. We have logged a ticket PDFANDROID-415 in our issue tracking system for its investigation and rectification. We will notify you as soon as it is resolved.
We are sorry for the inconvenience caused.