What is BlurHash?

In short, BlurHash takes an image, and gives you a short string (only 20-30 characters!) that represents the placeholder for this image. You do this on the backend of your service, and store the string along with the image. When you send data to your client, you send both the URL to the image, and the BlurHash string. Your client then takes the string, and decodes it into an image that it shows while the real image is loading over the network. The string is short enough that it comfortably fits into whatever data format you use. For instance, it can easily be added as a field in a JSON object.

See the website https://blurha.sh/ for images and further explanation. There is also a Python implementation available.

This can be used in the Hydrus UI itself as placeholders until thumbnails load. It would also be very useful to make it accessible through the API so clients can display the blurhash until the thumbnail loads.