Img.vision - Image hosting & video hosting for eCommerce sellers
The Product Folks - A volunteer-led community of product managers and makers
UploadHouse - Thumbnail and resize your photos and images
Product School - The global leader in product management training
ImageVenue - ImageVenue is a great online hosting service that allows uploading pictures for showing creative works with a simple-to-use technique.
Intercom on Product Management - The ultimate resource for aspiring product managers