To compare two revisions of an asset, open the Asset Details page and go to the Revisions tab. Then use the checkbox to select the revisions you would like to compare and click on the Compare button.
The two revisions open side by side and shows both the asset previews as well as the metadata of both revisions. Use the links at the top of the comparison overlay to toggle between showing All metadata or only differences in metadata in the two versions.
Differences in metadata fields will be colored to be easy to spot: green ones indicate that metadata has been added, red ones indicate that metadata has been removed.
FotoWeb Pro compare two revisions
In FotoWeb Pro, select the asset then open the Revisions tab to display the list of revisions. Tick the checkboxes of the two revisions you want to compare and then click the Compare button at the bottom to show the Compare Revisions window (as seen above).