ImagePost is an Android app that registers itself as a share activity in the system and accepts image and video files to upload to a server via HTTPS POST requests. This allows you to send photos very comfortably and quickly, e.g. via an instant messenger on your computer.
The server runs a PHP script which checks incoming images for validity, indexes them in a MySQL database and sorts them into folders. Another script and some lines of mod_rewrite-rules make it possible to call the URL with the image like a "normal" URL with a static image file. This request is processed internally by the web server via PHP and the corresponding image file is retrieved from the database.