Anomaly Detection from Data vs Image

[hscj87]

I was assigned with project to do anomaly detection on for all our company KPIs. I googled and found AnomalyDetection by Twitter. There was an idea from my colleague to do the anomaly detection on the graph images (comparing with previous week images to identify anomaly points) instead of using time-series raw data.

I am not familiar with the Anomaly Detection, anyone here experienced and able to advice which one is better (Anomaly Detection from data or image) in term of accuracy, storage and processing time.