Another small but annoying UI issue that occurs when trying to export JPGEs is;
If the Projection is set to Web (Web Mercator/EPSG:3857), and then you select JPEG you cannot then set the projection to Desktop (WGS84/EPSG:4326).
Now why some folks may want JPEGs in Google Earth or elsewhere. Most people just want the JPEG. They don’t need the KML n other file TFW ( whatever that is.
My suggestion is; Let Users select whichever projection they like whether JPEG or TIFF