DISCLAIMER: Modifying BTA voids your warranty. The BTA Team does not offer technical support for errors that arise from you changing BTA mod files. Always make a backup copy of anything you're going to change as it's quite easy to inadvertently break the game if you don't know what you're doing. If something seems to have broken beyond repair clear out your Mods folder and do a fresh re-install to correct any issues.
Other than that, it's also highly recommended you keep backups of any custom content you add to BTA. Updating your game files when a new patch comes out may overwrite or remove your changes.
With that out of the way, there are a couple of simple things you can do to customize your experience in BTA including adding custom commander portraits, company emblems and so forth. We'll cover a few of those here.
Custom Commander Portraits
Adding new portraits for your commander is quite simple. All you'll need is a 256x256 pixel sized image in either .png or .dds format. (.dds is preferred but isn't essential, it's just a smaller file and less taxing on the game if you add in a bunch of new pictures compared to if you were to add a bunch of .png files). It also helps if your image has a transparent background but it's not necessary.
Please note: .dds files will need to be either DXT1 or DXT5 compression, other types won't work. Also, due to the way .dds files are read, your .dds images will need to be upside down.
As an example, I'm going to add this .png Bounty Hunter portrait to my game:
Once you have your image, open up file explorer and find wherever your BATTLTECH install is located. You'll then need to open up the Mods > CommanderPortraitLoader > Portraits folders:
Note how all the images are upside down. This is because they're all .dds format images.
From here, simply copy your custom portraits in. Here's what it looks like on my system:
And you're done, as easy as that. Now just load up Battletech and when you start a new career your custom portrait will be available for you to pick in your commander creation:
Custom Company Emblems
Adding company emblems in is essentially the same as adding commander portraits. You'll need a 256x256 pixel sized image in either .png or .dds format. It also helps if your image has a transparent background but it's not necessary.
Once you have your image, open up file explorer and navigate to your BATTLETECH installation and up open up Mods > BT Advanced Emblems > emblems:
BATTLETECH\Mods\BT Advanced Emblems\emblems
Place your custom emblems in there and then load up the game.
As an example, I'm going to use this .png Hell's Horses logo for my company:
Add it to the BT Advanced Emblems\emblems folder:
Load up the game and go to Customize Company in the Captain's Quarters and find your fancy new company emblem: