JPEGifier

Hosting

First, generate keys with genkeys.sh (will need to chmod first) or create a keys directory and install your server keys. Make sure to name them key and key.crt.

Then, install dependencies with npm install and run with node index.js. Tested on NodeJS version 16.13.0 and 20.7.0.

Usage

Make an HTTPS POST request to port 8000 with the following settings:

• URL: /jpegify
• Content-Type Header: "image/png" or "image/jpeg"

The server will reply with the JPEGified image.

Requirements

• NodeJS
• Jimp (via npm)
• Docker (Optional)

Docker Commands

Follow the key generation steps from Hosting.

Build image: docker build . -t jpegifier

Run daemon: docker run -d --name jpegifier -p8000:8000 jpegifier node index.js

Example Output

Methodology

The methodology is simple. First, the image is scaled down to a fifth the size and scaled back up using the nearest-neighbor method. Then, a posterize filter is applied. It emulates the JPEG look pretty well, but it is not quite the same as exporting from Gimp at lowest settings. I find this to be a good enough approxmiation, especially for simple amusement.