CopyTrans HEIC for Windows - A plugin that lets you view HEIC photos on Windows and convert them to JPG by right-clicking.
Flickr - image and video hosting website
XnView MP - XnView is a free software that allows you to view, resize and edit your images. It supports more than 500 different formats!
Imgur - Imgur is a free and simple image hosting service with image editing feature. Signup is optional.
iMazing HEIC Converter - iMazing HEIC converter is a free Mac and PC app which converts photos from HEIC to JPEG or PNG.
PhotoPrism.app - PhotoPrism® is an AI-Powered Photos App for the Decentralized Web. It makes use of the latest technologies to tag and find pictures automatically without getting in your way. You can run it at home, on a private server, or in the cloud.