UploadHouse - Thumbnail and resize your photos and images
match.color.io - Automatically match colors of any image or movie with ML
ImageVenue - ImageVenue is a great online hosting service that allows uploading pictures for showing creative works with a simple-to-use technique.
Color Palette Generator - Enter the URL of an image and find its color palette
Img.vision - Image hosting & video hosting for eCommerce sellers
Colores - Find color palette ideas via image search