I hardly see some ship size comparison photos. Here's one I decided to make between two classes that we know of from canon Star Trek.
The Constitution class refit 1701, and The Next Generations' Galaxy Class Enterprise.
The last three I decided to do between a canon 1701 refit with the non-canon Excalibur class. And boy was that ship a real giant. I'll let the pictures speak for themselves.
Also the two ships are as close as I can get them without the other ship flying away from me. I'm only using single player QB in these shots. So these were done with the 1701 as my player ship and the other is the AI friendly ship. I got as close to about less than 0.5 km distance to the other ship.