DAM for Sitecore has a tool for cropping images in DFS which will crop around a focus point. From the system there has been defined predefined aspect ratios, that is allowed to crop. The tool will not touch the original asset. Instead, it creates a new assets, which is an edited version of the asset. It is an independent asset, but it descents from the original asset and will inherit the metadata too. You can read a more deailed description hereMM5.7 Asset editing (crop and trim).
