REST API is in Microsoft Information Server configured by default to transfer binary data of maximum size of 65KB.

The size is configurable by parameter maxReceivedMessageSize in web.config file located in API directory.

<!–Defines a standard endpoint with a fixed <webHttpBinding> binding that automatically adds the <webHttp> behavior. Use this endpoint when writing a REST service.–>
<standardEndpoint maxReceivedMessageSize=”4194304“/>