There appears to be something wrong with the zen_colorbox function that is causing the image filename not to be returned, something similar to what was happening before. Would check to validate that the correct file has been uploaded.
As to the image "size", in the html, I don't see a size discrepancy. Would have to look around to see how the image is "appearing" as 50x50, but don't see anything obvious. On my device it takes the full screen when selecting the additional images.
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