Jpeg.io is a free online interface for rapidly and conveniently converting your images into highly optimized JPEGs using Kraken.io's proprietery JPEG optimization algorithms. It has been engineered with simplicity in mind: simply drop your image into the drop space and a short time later you'll get a progressive JPEG compressed to the smallest possible size without perceptible quality loss.
Jpeg.io supports the image formats you care about, including JPG, PNG, GIF, SVG, BMP, EPS, PSD, TIFF and WEBP.