I have had problems with Autoformat ding odd things with spacing if it is used on very uneven spacing as is the case when I first enter a score.
I have found the Score drop-down menu entry for Layout to be much better, I usually opt for 4 bars per line then let Autoformat deal with minor spacing corrections after I do any editing.
For image attachments it would appear that you are forced into using something like DropBox or GoogleDrive and just providing a link.