I would like to request the ability to automatically group/stack images based on visual similarity.
Current Limitation:
digiKam has a powerful Similarity View and "Find Duplicates" tool that uses Haar wavelets to identify visually similar images. However, once these matches are found, there is no automated way to "Stack" these results into groups. Users must currently perform manual selection or use the Light Table to manage these items one by one. 
Proposed Functionality:
"Auto-Stack by Similarity" Button: Within the Similarity/Duplicates results view, add a function to automatically create stacks for all identified match groups.
Threshold Control: Allow users to set a similarity percentage threshold (e.g., 90%) for the auto-stacking process.
Cross-Folder Stacking: Enable the option to stack these similar images even if they are located in different physical albums/folders.
Rationale:
This would significantly speed up workflows for photographers who take burst shots or brackets. While "Auto-stack by Time" exists, visual similarity is often a more accurate metric for identifying images that should be managed as a single logical unit.