Similar to vector data exchange formats, there are a lot of raster formats out there. There are formats storing rasters in binary form and in ASCII form. We can even save rasters like vectors in QGIS with the Save As tool accessed from the raster layer's context menu in the Layers Panel. If we see the save dialog with the srtm layer, it is slightly different from the vector version reflecting the specialities of the raster data model. We can set a CRS and ask QGIS to transform the raster to another CRS (it is called raster warping). We can also set the extent and the resolutions in both dimensions manually. There are some other options too; however, they are GeoTIFF-specific. What is very unusual, though, is that we can hardly access any format other than GeoTIFF from this menu.