Client side image editor is the first thing I thought of.
[1] https://developer.mozilla.org/en-US/docs/Web/API/Canvas_API/...
I'm pretty sure the applied css effects should carry over to the canvas.
Recently, I've been looking more into WebGL and what's possible with GLSL shader scripts for image warping (for VR) and image processing/effects. see shadertoy.com etc.