How to compress image: upload the picture you want to compress/optimize, and then scroll to see/download the optimized image. Optional: you can select quality of compression and other settings, like max width, final height, etc. After uploading, this tool will show you useful info about original image (size, timestamp) and about compressed image (new size, % of compression)
Select quality compression, from 10 % (high compression, high speed loading, low quality image) to 90% (little compression, low speed, high quality image). Default: 80%
You can define some properties of final optimized image, like max width, max height, final width, final height, etc.