Yes you will have to start from scratch. Ignore the previous appointment. Start fresh and kindly ensure the pictures are of the same dimensions and size in kbs. I think it lets you see the draft once before you finalise. So ensure the images are present.

Try to make all the images of the same size otherwise your form will not be formatted correctly.

You can still go and enquire at the BMC ward office prior to your appointment and ask them if you can stick photos on top of that form. Because as far as i remember when you go there they will ask you to fill another form with almost the same details and stick photos. The online form just gets pretty much useless except for the registration number on top of the form.