Ansel is a non-destructive image editor and opens all images in read-only mode. Any data created within Ansel (metadata, tags, and image processing steps) is stored in separate .XMP sidecar files. These files are stored alongside the original Raw files and allow Ansel to store information about the images as well as the full editing history without touching the original raw files. When you import an image into Ansel for the first time, an XMP file is automatically generated.
When importing an image, Ansel automatically checks if it is accompanied by a sidecar file. As well as looking for files named <basename>.<extension>.xmp and <basename>_nn.<extension>.xmp (Ansel’s XMP file naming formats) Ansel also checks for the presence of a file in the form <basename>.xmp (the naming format for Lightroom’s XMP sidecar files). Files with the latter naming format will be read by Ansel but will not be written to. Once the image has been imported, Ansel will generate an additional XMP file using its own naming convention.
Many users have huge image collections stored on extra hard drives in their desktop computer, or on an external storage medium (RAID NAS, external hard drives etc.).
It is a common requirement to develop a number of images while travelling using a laptop and then later synchronize them back to the original storage medium. However, copying images manually from the main storage to the laptop and back is cumbersome and prone to errors.