Please stop trying to upload through Bridge. Just put the card in your computer, open the folder (go to "My computer" if the folder doesn't open automatically) then copy the files safely to the correct folder on your hard drive. Don't overcomplicate life.
Hi Stacey, may I see a screenshot showing the whole screen? Well, at least the layers panel.
Oh, also, make sure you zoom in to 100% to see if the line is really there. Sometimes this occurs as a trick of zoom.
The nature of your question indicates that you didn't use the Shape Tool to make vector clipping masks the way you should have?
https://www.damiensymonds.net/2011/12/simple-clipping-mask-and-storyboard.html
If you had done so, you'd simply Ctrl T the shape layer and change its size/shape to your heart's content.
As long as you share links to them, it's absolutely fine. Make sure it's a link to the page they're on, not directly to the image. We need to give credit to the owner.
ALWAYS edit in your bright room. I can't stress this enough. It's so important.
Yes, if the prints are brighter than your screen, calibrate again with a higher brightness target.
This is almost always a good thing. Screens are always too bright before you calibrate them.
The important question is - does your screen match your prints now?