What are some alternatives?
ImageKit.io - Instant multi-platform image optimization
Squash 2 for Mac - The easiest way to compress and optimize images for the web
Shrink Me - Compress images with one drag / click
TinyJPG - Compress JPEG images with perfect quality and file size
Landscape by Sprout Social - An interactive tool for social media image resizing
TinyPNG - Make your website faster and save bandwidth. TinyPNG optimizes your PNG images by 50-80% while preserving full transparency!