Tutorial: Steam mod icon Last edited 2 months ago2024-08-31 16:49:59 UTC

So you've made some Half-Life mod. Maybe it's some fun singleplayer campaign, an obnoxious content replacement pack, or a class-based team multiplayer where you battle as Xen creatures. No matter what your mod is, the point is you want a nice little icon to show up next to its name in the Steam library and in the game window's title bar.

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There's only 3 files you need to worry about: game.tga, <iconname>_big.tga and liblist.gam.

game.tga	This is the icon that will be visible in the window's title bar. It may be anything from 16x16 to 48x48 pixels as far as I'm aware, and can be either a 24bit or 32bit .tga (32bit if you want to include the alpha mask for transparency).
<iconname>_big.tga	Can either be a 24bit or 32bit .tga or a .png file (32bit .tga if you want to include the alpha mask for transparency).

For liblist.gam you need to add the line

icon "<iconname>"

Make sure to replace <iconname> in liblist.gam by the desired name without any file extension. Make sure to rename properly <iconname>_big.tga. Some use the mod's name here, others simply use "game".

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It appears game.ico and <iconname>.tga are unused, at least in the Steam version of Half-Life (tests made with the latest 25th Anniversary version on Windows both with Software and OpenGL renderers).
None of the mentioned icon files appear to be used for the shortcut when pressing Add desktop shortcut in Steam.

Recommended setup: the mod icon should be a 32x32 TGA 24 bits uncompressed file named "game.tga". This will be shown in the Windows toolbar (and in the title bar when playing in windowed mode as well). If your mod is not "self-published" on Steam (like Cry of Fear, Half-Life: CAGED, Sven Co-Op), duplicate this file to "game_big.tga" and add the icon "game" key/value pair in liblist.gam so that it is displayed in the Steam client library.

If you want your mod icon to have transparency, you must generate an alpha mask. To do this using Photoshop:

1. In the layers tab, right click on the layer thumbnail and choose Select Pixels
2. Select the Channels tab
3. Click the Save selection as channel icon at the bottom of the tab (you can leave the visability layer hidden after your new Alpha 1 channel is created)
4. Save your icon as a 32bit .tga (ensure the Alpha Channels box is checked in Save options)

If your mod icon is flipped upside down in the toolbar, you can use this tool to fix it.