These are features we consider to be essential for an ideal image optimization tool/service. These general features are those that should be available in anything that is promoted as a way to improve a web site’s image performance.
Why
Accepts modern image formats as input
Can it use modern image formats as a source for your optimized image?
3Sub Tests
Returns smallest format possible automatically
Does the default response give you the smallest format possible?
13.5/20Tools Passing
akamai 
bigCartel 
cloudflare 
goDaddy 
imageEngine 
imgproxy 
optimole 
shopify 
shortPixel 
squarespace 
thumbor 
wix 
cloudinary 
fastly 
imgix Handles image metadata
Does it remove cruft, but keep licenses and attributions?
2Sub Tests
Outputs modern formats
Can it produce modern image formats?
2Sub Tests
Automated psychovisual optimizations
Offers automated psychovisual optimizations (e.g. via machine learning) to increase compression without perceivable visual impact
3/20Tools Passing
imageEngine imgproxy shortPixel
