Econa does not work with 'JPEG' file extensions, only 'JPG'?

I just ran into an issue where a user uploaded images with .JPEG extensions, and Econa would not save them in the content editor. We are using custom fields if that matters. Changing the extensions to '.JPG' worked, but why do we have to do this? If it matters, we have 'Convert to JPEG format' turned off because we sometimes use PNG files.

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