The Synchronize Folders function helps you maintain a copy of photos from a chosen source in a chosen target location. It works in two steps. First the contents of the Source Folder and Target Folder are compared, and the program recommends a list of file copying/deletion actions to be made for synchronization. Then after confirmation and any desired changes, these synchronization actions are actually taken. The recommended synchronization actions can differ based on the selected Synchronization Method. Symmetric means that a successful synchronization copies files from the source to the target and vice versa so that after synchronization, they both have all the files that were in either the source or the target at the start. Asymmetric comparison is one-way: only source files missing from the target are marked for copying. Asymmetric, Delete in Target is similar, but also deletes from the target anything not in the source.
A proposed synchronization action is listed for each item in the operations column. An arrow means copying in that direction. An X means deletion. An equals sign means the files are the same (this is only shown when Hide duplicates is not checked). A "not equal" sign is shown for files that differ, but for which no action will be taken. Click on an operation to change it. Changing a folder operation (these are shown with a gray background) affects all operations for files and folders under that folder, in cases where that is appropriate. The direction in which files are copied (for the Symmetric method) is decided based on which copy was changed more recently.
The Synchronize button starts the actual copying and/or deleting of files. To have the opportunity to view and, if desired, to disallow operations one-by-one, turn on Confirm file operations.
Run the mouse cursor over a folder name to see a bubble showing the full path to the folder. Run the mouse cursor over a file name to see the full path to the file plus its date of last changes and its size. For files that exist in both the source and the target, information about their comparison is shown in bubble help above the Operation field. A short summary of the planned synchronization is displayed under the file list.