Problems importing and projecting images.

[DevonF]

I am experiencing at least two major problems. First is not bring able to open GeoTiffs but can open pngs fine. But then the PNG file is projected 5 orders of magnitude too small, and still in the wrong place.
I can upload the image I'm using if anyone wants to test with it.
Using JOSM 11223 with ImportImagePlugin 32699

QGIS:

-install georeferencer plugin
-raster -> georeferencer -> georeferencer

-import image, pick some points (say 4). (save the points if need to use again)
-Use EPSG:3857 projection (same as OSM slippy maps ​https://wiki.openstreetmap.org/wiki/EPSG:3857)
-run to get a GeoTiff out.tif

-create a world file (.tfw file) and projection file (.prj): raster -> projections -> extract projections. Select geotiff file, select create .prj file and generate. Can also use listgeo -tfw out.tif

JOSM:

-install ImportLayers plugin.

GeoTiff:

-with the tfw and prj files (same name as geotiff) open the geotiff image out.tif(imagery -> import image or file -> open). get error:

19:11:22.851 [AWT-EventQueue-0] ERROR org.openstreetmap.josm.plugins.ImportImagePlugin.LoadImageAction - Error while creating image layer:
java.lang.IllegalArgumentException: ImageRead: No OperationDescriptor is registered in the current operation registry under this name.

-remove the .prj file and and try again. get error:

19:10:42.229 [AWT-EventQueue-0] ERROR org.openstreetmap.josm.plugins.ImportImagePlugin.LoadImageAction - Error while creating image layer:
org.geotools.coverage.processing.CannotReprojectException: Can't reproject grid coverage "out".

-create a new layer and try again. get error:

19:11:22.851 [AWT-EventQueue-0] ERROR org.openstreetmap.josm.plugins.ImportImagePlugin.LoadImageAction - Error while creating image layer:
java.lang.IllegalArgumentException: ImageRead: No OperationDescriptor is registered in the current operation registry under this name.

PNG:

-convert tiff to png (convert out.tiff out.png)
-open out.png with the twf and prj files. get error:

22:23:00.486 [AWT-EventQueue-0] ERROR org.openstreetmap.josm.plugins.ImportImagePlugin.LoadImageAction - Error while creating image layer:
org.geotools.coverage.processing.CannotReprojectException: Can't reproject grid coverage "".

-remove the .prj file and and try again. This time asks to use default image projection (EPSG:31467) or JOSMs current projection (EPSG:3857).

-select default: black rectangle.
-JOSMs current: works with image ontop of black rectangle. However image is at coordinates of ~0.0004, 0.0006. The world file looks like:

0.00004919
0.00000000
0.00000000
-0.00004919
-76.05813998
45.58612271

multipling the numbers by 10⁵ I get the coordinates with the correct order of magnitude, but the image is still 1000km out. The world file format (​https://en.wikipedia.org/wiki/World_file) is pretty simple so it must be a problem with the plugin. What's weird, is looking at the layer properties (using the normal world file), it shows the correct coordinates but clearly isn't projected properly on the map.