The low resolution setting is 640x480.  If you have  a higher resolution setting on the GoPro camera, it will now be downloaded to Myk unless the high resolution setting is enabled in the Myk settings (for auto-download and mixing), or you select the High Resolution option when you download the file to Myk.  Some higher resolutions in the GoPro do not offer a lower resolution version on the camera.  In this case, Myk will download the high resolution version.