Zabbix - Track, record, alert and visualize performance and availability of IT resources
ImBatch - ImBatch is a batch image processor with a nice graphical user interface.
Datadog - See metrics from all of your apps, tools & services in one place with Datadog's cloud monitoring as a service solution. Try it for free.
Batch Image Resizer - Resize, crop, shrink, flip, exif-rotate, convert, enhance, process multiple pictures and photos with professional software! 120+ Actions, 30+ Image Formats
Prometheus - An open-source systems monitoring and alerting toolkit.
Ralpha Image Resizer - High-speed image batch conversion tool