more troubles in QGIS. I georeferenced this raster in Corrego Alegre UTM23S and loaded up, so project CRS automatically changed to that. So far so good. I need it to be however in WGS84 UTM 23S. None of the two possible ways will do. Enabling OTF reprojection and setting project CRS to WGS84UTM makes the raster layer disappear. Even after "zoom to layer". It's just not visible. The other way would be to save the layer in a different CRS with right-click-save as. Doesn't work either. I just did as other times before, but the file is not saved. I open the folder where I sent it to, and it's not there. Please help.
Rightclick -> Saxe As ... to reproject a layer only works for vector layers.
Raster layers are a bit more complicated, you have to use
Raster -> Projections -> Warp(Reproject) with a new file name and source CRS different from target CRS.