Hi Samantha,
1- You cannot directly connect to a camera via Bluetooth with Survey123; however, if your camera can move the photos to your device, you could then select the photo. We are working on being able to directly connect with devices such as cameras; could you respond with the camera information so we can log it as a connection example?
2- There is a limitation on photo upload to 10 MB; this may or more not meet the requirements of 'high resolution' - this could be in the neighborhood of 75 megapixels for a JPEG, or much less for TIFF or RAW files. The size limit is a limit of how Survey123 handles files, not the ArcGIS platform; we have an outstanding issue to improve this in the future.
