Update README.md

README.md

 x393
 =====
 
-![x393 Block Diagram](http://docs.elphel.com/x393_diagram.svg)
+![x393 Block Diagram](x393_diagram.svg)
 
 FPGA code for Elphel 393 camera, created with [VDT plugin](https://github.com/Elphel/vdt-plugin). It runs on Xilinx Zynq 7030 SoC (FPGA plus dual ARM).