jakaskerl, using the link you shared previously I understood what I was forgetting, I combined it with the code I use to display the distances and now I no longer have the image cropped to 300x300 but with camRgb.setPreviewKeepAspectRatio(False)
I can use the entire frame of the cam.
Thanks, and sorry if I bothered you but I've been studying the library these last few months.