If you’re developing on a Mac, ImageOptim can handle all of the image compression (JPG, PNG, etc): https://imageoptim.com/mac
For SVGs, svgo (brew install svgo) usually produces the best results for me.
svgcleaner is supposed to be faster and have a better compression ratio than svgo: https://github.com/RazrFalcon/svgcleaner
It also has a GUI.