Basically you won't have enough RAM on the ESP8266 to store a full 128 x 160 x 16 bit image, so you can either draw each pixel as it's needed (easier to implement, but slower). Or store a lower bit depth image in RAM with a color palette. The ILI9163 module offers both options, so you can pick and choose.
Probably the first one is easier.
If you do get it working, please can you contribute your code back? It'd be great to have something that everyone could use
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
This is the actual ST7565 module code: https://github.com/espruino/EspruinoDocs/blob/master/devices/ST7565.js
However the ST7735 looks like the code will be more like this: https://github.com/espruino/EspruinoDocs/blob/master/devices/ILI9163.js
Basically you won't have enough RAM on the ESP8266 to store a full 128 x 160 x 16 bit image, so you can either draw each pixel as it's needed (easier to implement, but slower). Or store a lower bit depth image in RAM with a color palette. The ILI9163 module offers both options, so you can pick and choose.
Probably the first one is easier.
If you do get it working, please can you contribute your code back? It'd be great to have something that everyone could use