I have looked at solutions to what seem to be somewhat similar problems but they don't seem to solve my problem. A georeferenced raster layer loads into the correct location in relation to other layers, so CRS is obviously OK, but has this black background which I don't know how to remove.
To remove the black border temporarily in QGIS, you can set the "Additional no data value" in Layer properties -> Transparency to
0 (or 000000). If the border is not 100% black you can use the information tool to find out which color you need to set to transparent. If the border is not evenly black, you can use the custom transparent pixel list in the same window below.
If you like to permanently remove the black border in your image by adding an alpha channel, you can use the GDAL Tool
nearblack: Go to Raster -> Analysis -> Near Black and set the in- and ouputfile, then use the edit pen to add
nearblack -of GTiff -setalpha -o output.tif input.tif
(Of course you need to set output.tif and input.tif to your needs)
Add the None band and set the RGB values to 0-0-0, Certainly the black background goes. https://i.stack.imgur.com/xD94j.png