If you’re installing ImageMagick 7+ on Windows then you will need to tick the
Install legacy utilities (e.g. convert) box or Piwigo (2.9.5) won’t detect it. The installer should take care of adding the binaries to the system path.
Maybe this step won’t be necessary in future versions of Piwigo. It looks like some ImageMagick functionality is planned to move to Poppler (Windows builds). This uses the Cairo Graphics Library, which is supported by PHP too. However, none of these tools are particularly modern.
One of the most exciting modern image libraries is ImageSharp, which as the name suggests is written in C#. It aims to better the functionality traditionally provided by
System.Drawing (and WPF alternatives) in .NET. The legacy libraries were designed for the Windows desktop and never intended to run in a web environment. I’ve seen first-hand how they can cause memory leaks!