According to
https://developers.arcgis.com/net/layers/add-raster-data/ The SDK can handle .jpg and .jpg 2000 formats. When I attempt to load a map .jpg into a Raster Layer, add it to a GroupLayer, and then add GroupLayer to Map.Operational Layers, I receive the error: File error: Failed to open raster dataset: C:\Charleston\Charleston-JPG\charleston.jpg. I am able to create Rasters for RPF (CIB), RPF (CADRG) and GeoTIFFs with no issues.