Feature: load single image as reference camera

[johhnry]

Is there an existing issue for this?

• I have searched the existing issues and added correct labels.

Please describe the feature you have in mind and explain what the current shortcomings are?

Currently we can import an image sequence as a Sequence Camera. It would be nice to be able to also import a single image as Reference Camera like explained here:

https://jamesprattvfx.wordpress.com/2018/10/01/using-reference-frames-in-3d-equalizer/

Suggested implementation?

Implement a Load plugin like load_plate.py

Describe alternatives you've considered:

No response