Store Published Image into cv2.VideoCapture()-Like Object

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Folks,

How can I store published images into a video-like OpenCV object, without having to create a video file (e.g. .mp4) first? Does not have to be a VideoCapture() object, but just any object that stores all the frames (I don't think a vector/list is what I'm looking for, but an actual OpenCV object...if possible, of course).

I'm trying to use a program called bag2video.py to do this as well, but I don't fully understand how the program actually works.