send images from remote server to mobile

I have a web platform in which the user enters the data, which are stored in SQL database. Using restful services and json I send the data in my mobile application via http calls, and I save them in sqlite database. The above works perfect. Now I want to upload images in web platform (which will saved in a separate table in SQL server) and in continue I want to get the images in mobile app, in the way which I have done for other data. After a lot research in google I found the blob data type. So , if I save the images as blob in sql then how can I convert them as json objects? Moreover, I want to know if it is efficient.