I found an issue in your import file screenshot. You need to update origin.id, origin.url, origin.width and origin.height in the thumb_mobile_view. All values for these keys should be the same as in the main image title_rectangle_image.
Give this a try and let me know if you have any questions related to it.
It's possible to upload different images with multiple views. Just keep the origin.url data for the thumbnail and nothing else. Give this a try and let me know if you still find any issues.
There is no solution to import a document without editing it ?
The problem is that if we have a lot of files with different thumbnails, we will have to spend a lot of time editing all the import files to remove all the data.
The import module has some limitations, one of them is that it automatically regenerates thumbnails based on the origin data for the main image specified in the import JSON file. Thus, image data you provide in Import JSON files for responsive views of a given image field are ignored in the importing job.
If you're looking to make a major update to a lot of documents without affecting custom images already uploaded in existing responsive views, the only option I see is to deport this custom views data into specific image fields (so in your case adding 2 dedicated image fields for thumb_tablet_view and thumb_mobile_view) and adapt the queries in your code accordingly.
Note that this will also change the way content editors will see these 3 images: they'll see 3 image fields in the editor instead of one image component with multiple bullets allowing to edit the views.
I hope this clarifies the option and sorry for the inconvenience it might cause in your case.
