I have a 2048x1024 PNG representing a WGS 84 projection of global data, where pixel 0,0 is lat 90 lon -180 and pixel 2047,1023 is (just shy of) lat -90 lon 180. When I add it as a raster layer in QGIS (specifying WGS 84 as the CRS) it's pulling in as pixel 0,0 = lat 0 lon 0 and pixel 2047,1023 = (nonsensical) lat -1023 lon 2047.
How can I fix this? I've messed around with the Raster menu a bit to see whether that helps, but didn't figure anything out. Perhaps I need to define a custom projection to translate and scale?