Created attachment 107803 [details]
This dialog will need rewriting

Currently digiKam offers the ability to write to sidecar XMP files based on whether they are RAW or not, or whether they're read-only or not. 

In my workflows, digiKam organizes new incoming RAW images, other tools convert them, blend them and otherwise manipulate them into 16-bit TIFFs and then I use a digiKam workflow to apply local-contrast and ICC profile adjustments before sending them over to ownCloud for use on another device altogether.

As such, I typically have several or even many large (350MiB+) in-flight TIFF files in a directory. I seek to minimize filesystem-bound delays assigning and writing metadata and to move the annotation process earlier in the workflow (so that all future versions might inherit).

Proposed enhancements:
1) "lazy sync" is still bound to do only what is configured, ie write to XMP and/or file - it just allows batching-up edits. Please add a second option to forcibly *embed* the XMP into the corresponding base image file for all selected files (TIFF and JPEG; RAW formats subject to existing logic).

2) Use file-size and/or file-type as other factors in the logic determining whether writes affect XMP or not. Examples: "write to file and sidecar if size < 100MiB"; "write affects only the sidecar if file is [RAW] or [TIFF]". Etc. 

Between these two options, I would be able to build a database of metadata stored in both digiKam and XMP for safety, potentially in several operations over several visits, and *then* commit it to all the TIFFs in bulk once I'm ready. Minimal file-i/o, maximum convenience.

Thanks.