Get a copy of hpk.exe from https://github.com/nickelc/hpk/releases
(if you're uncertain of which file: x86_64-pc-windows-msvc.zip)

Put this in a batch file (make a new .txt file and rename it to extract.bat)


Copy hpk.exe, somefile.hpk, and extract.bat to the same location.


Run extract.bat.


Google what you don't know.
https://www.makeuseof.com/tag/write-simple-batch-bat-file/

To create hpk archives use: hpk.exe create FolderContainingFiles ModContent.hpk

If you're wondering why your image editor/exporter doesn't work with DDS files from Armstrong update (quote from dev):

For the UI images shipped with the game we switched to BC7 compression format, which we store in DDS files. We use Intel's ispc_texcomp conversion library (on GitHub).
Because BC7 works on 4x4 blocks of pixels, and thus requires image dimensions to be multiples of 4; we internally pad the images to 4x4, but still store the "real" dimensions in the header, because we need the exact original size to do UI layout. This probably makes them look corrupted to some tools.

You can directly edit them in Paint*NET[getpaint.net]

Or you can use Texconv[github.com] to convert them for other programs:
(or png)
To convert images to the dds format used by the game:

To get a copy of texconv.exe: look for releases with 5 assets
https://github.com/microsoft/DirectXTex/releases

Chef Niko:
Script to convert dds to png using texconv. Place texconv in c:\ and run the script from the root of the directories with dds files in them.


You can use my ECM mod to extract mods (Menu>Help>Extract Mods).


If you're extracting lua files to decompile them; then add --fix-lua-files to help out unluac (more help[github.com]).