220.127.116.11.1.3.5 Stream Bitmap Orders
The stream bitmap alternate secondary orders (added in RDP version 5.1) enable bitmaps of arbitrary size to be broken up into 4,096-byte blocks and streamed from server to client, each block being sent in a separate stream bitmap order. All of the bitmap blocks MUST be sent in sequence. The bitmaps can be sent either compressed or uncompressed.
None of the stream bitmap alternate secondary orders include the cache entry in which to store the streamed bitmap. This is because the server MUST always send a bitmap creation order that contains the bitmap cache entry data immediately after streaming the bitmap bits to the client.
If support for NineGrid rendering is specified using the DrawNineGrid Cache Capability Set (section 18.104.22.168), the support for bitmap streaming is implicitly assumed to be the case, as the NineGrid bitmaps are transported using bitmap streaming.