What are some alternatives?
When comparing Piwigo and Pmwiki, you can also consider the following products
Chevereto - Chevereto is a powerful and fast image hosting script that allows you to create your very own full featured image hosting website in just minutes.
Gravatar - Gravatar (an abbreviation for globally recognized avatar) is a service for providing...
Google Photos - All your photos are backed up safely, organized and labeled automatically, so you can find them fast, and share them how you like.
Skore - If Evernote and Pinterest had a baby
MediaGoblin - MediaGoblin is a free software media publishing platform that anyone can run.
42matters Explorer - Explorer by 42matters is a research tool to visually explore databases of apps, publishers, audiences, SDKs, technologies, contacts and others.