It takes URL of your image and dimensions you'd like to receive. It creates the optimized version on the fly. Each image is then cached and afterwards served from local cache very fast.

Developers or site admins can not always use some reliable image thumbnailers. In such cases there is feezy always here for you. You can use it any time you have pure JS project, need to optimize any image on-the-fly or need to keep your codebase as slim as possible.

Yes.
The new image type is determined based on your new image name. If you put here "image.jpg", the final image will be converted to JPG.
This conversion works with most image type incl. modern ones as webp.