I am adding a raster in TIF format to my ArcGIS Online content. When asked to specify the type of content, "raster" (of any type) is not even an option. There used to be an "image collection" option but that seems to have disappeared. I ended up choosing "geodatabase" but this is not actually a geodatabase. The drop-down menu should be more inclusive of the types of content people may need to upload.
Also, we should be allowed to upload .7z files, not just .zip files.