Under the Image tab in Web Properties the Photo Pop-Up default value is 500pix. Other than creating a custom template is there a way to alter this size globally?

When using a photo grid I can't seem to find a way to alter the pop-up per grid, just each photo individually. For example: 6 photo grids with 6 photos in each grid. If the pop-up size needs altering, I ctrl click each photo and edit.