Hi Peter,
In TCM v2.6.1 , we don't have an option to show the project size. Can you please let us know ,where you are seeing this size. Is it in the App info option or some other place. It would be good if you could share a screenshot.
On a side note, the project size displayed will be different between Connect Web and Connect Mobile.
Connect Web calculates the project size based on file sizes on the server side.
Regards
Darshan Kamat