When using "Save Photos as" and scaling the image "to fit box:" and trying to use the "Rename as:" function in the "Save as:" "Operations" block to put the new image dimensions in the file name using "{filenamebase} {width}x{height}". 
Instead of the new dims, it puts the original file dims in there, though. 
The workaround is to use two steps: "Save Photos as" and then reselect the new files and rename them with the current {width} and {height} vars. 
Please create {saved_width} and {saved_height} variables that could be used to save and rename files in one step, as opposed to the two steps needed currently.
Thanks!