I get: PHP Fatal error Call to undefined function imagecreatefrompng()

If you get the error PHP Fatal error: Call to undefined function Matomo\\Plugins\\CoreAdminHome\\imagecreatefrompng() it means that you need to install the GD extension for PHP. The GD extension is required for Matomo to generate report graphs, generate sparklines graphs, as well as to upload a custom logo. To check whether the GD extension is installed on your server, go to Matomo settings (Administration) Settings Cog Icon > System Check.

Previous FAQ: How do I fix the errors « Unable to write in the cache directory » or « The directory matomo/tmp/cache/* » is not writable. »?