Useful for two things: you want to make new default pajamas for all your sims, or just one Sim in particular.

Using the steps you used to make your textures above, make your pj's. Though as a note, unless you know how to change the default body mesh in the game, make your pj's have long sleeves and long pants, though sometimes through careful arranging of lines, you can make it not so noticeable.

for a change to the default PJ's .bmp like new colors or something:
female: name it as PajamaFlgt_01, PajamaFmed_01, and/or PajamaFDrk_01
male: PajamaMdrk_01, PajamaMmed_01, PajamaMLgt_01

To change it to just one character, rename as above, except change the 01 to whatever your end tag is, like PajamaMdrk_maul

Put the finished product in the skins folder of the game, or preview in Simshow.

The trickiest of them all in my experience. These are the source of most of my e-mails.

Through no logical reasoning, the swimsuits that are intended to be just for one skin, end up taking over all of them It didn't use to at first, on mine, but the more skins I had, the more often it happened, and there is no reason it should do it to begin with, but it does.

I realize that's probably confusing. So I will go step by step, somewhat.

If you're making a custom swimsuit, chances are you made a custom nude skin and Pj's as well. Using Maul as an example again, because of his unique coloring, he needed a unique nude texture, as well as a unique pj's and since he will be showing some skin when he swims, and some custom swim trunks. (not that he wasn't a total hottie in those pink speedos. )

For the easiest results, I loaded up Maul's nude skin, and made a pair of swimtrunks over it.

Ok, now that you have a custom suit and have put it in your games Skins directory, make a default to "match" it.

Get the default suit, or something with the "sim"suits bmp and rename it to UMFitdrk_01:

If you actually want to make a default replacement of your fit or what have you category swimsuits, then design whatever suit you want and rename it

male: UMFitdrk_01, UMFitmed_01, and UMFitlgt_01
female: UFFitdrk_01, UFFitmed_01, and UFFitlgt_01

To rename for your custom suit, use the UM .bmp for the skin tone you are using (lgt, med, drk) , and just replace the _01 part with the end tag of your body .bmp .

You can also custom design a formal outfit for your sim. Just be sure you design a long dress for your female and a tux-style for your male unless you know how to change the default body mesh.

The naming for this is:

male : FMFitlgt_?, FMFatmed_?, and FMSknlgt_?
female: FFFitlgt_?, FFSknmed_?, and FFFatdrk_?

the "?" is for whatever end tag you have. These will also go into the "skins" folder of the game.