So, if I upload to Google Street View, they say they can use my photos in all Google services (more like a contract, not CC).
Mapillary → CC BY-SA, so anyone must write “(c) username – Mapillary” if they use it.
Question: if I upload to Mapillary, then to Google, do I need to put “(c) username – Mapillary” inside nadir for the Google one? or no because I’m the author?
Other question: if I upload to Mapillary with 1 nadir, and to Google with other nadir (or no nadir), is fine? or maybe if I change contrast/colors between them, is this a different work or still same photo for license?
You are confusing 2 things - your copyright and licensing.
If you have taken photos yourself, then they belong to you. You have the copyright and all the intellectual and moral rights to it. Unless you explicitly transfer away your intellectual property rights (including copyright) for these photos with a legal contract or agreement, you can do with these photos whatever you want. This means, you can use them wherever you want, modify, upload, sublicense, whatever.
When you upload photos to Mapillary, you grant the rights to Mapillary to use these images and you license these images under CC for others to view, download and use. You do not transfer away your original copyright, you still own the photos. But now, with the public license anyone else can use these photos obeying the license. The rules, like adding attribution applies to other people using these photos. They might not be allowed to reupload them elsewhere. This does not apply to you - you have the full original copyright.
Same exact thing with Google Street View, you grant them a very wide license to do a lot of stuff with your photos, but you do not transfer away your rights to the photos.
So you can also upload the same photos elsewhere, because you own them. A bunch of people upload their photos to Mapillary and elsewhere, like GStreetView, KartaView, Panoramax instances, Mapilio, Commons, whatever. If you want to upload different versions to different services, that’s your right. You can modify and transform the photos however you like, none of this affects your copyright. You don’t have to add any attribution or anything like that - this is all secondary after you upload it to other services and applies to other people.
Exactly, both Mapillary and Google use non-exclusive licenses by default, so you still retain full rights and can upload the same or modified versions anywhere else without issue.
