Hi @grace-galdamez, if you end up doing the Photoshoping like I did, two suggestions:
1) Make it as realistic as possible. It could be that a photo they would have picked they decide not to pick for the reason that it looks fake.
2) I would submit to Dropbox both versions, the one that wasn’t Photohsopped, and the one that was. That way the publisher can see both and choose to do the Photoshop work themselves, or choose the work you did if it’s good enough.
And of course, be sure to save locally on your computer the original version that has had no Photoshop work done to it so you can always go back and re-do the Photoshop work if ever needed!