Imagify

When it comes to retaining your website visitors, speed is everything, people will not wait around for a slow website. Images can account for up to 50% of your loading time, so getting these optimised is vital.
Frontify is a premium image optimiser that integrates with a number of popular CMS’ (including WordPress of course), which can reduce your image file sizes by up to a whopping 70%. There are number of price plans available starting at just $4.99 per month.