My textures thread has the UV map as a separate image if you want to download it. It also has a working Batgirl costume on page 2. :D
There are links to download the texture files in .psd format in the first two posts in this thread, or you can build one as per the "Talk to the face; the boobs aren't listening" texture in my thread and play from there.
If you download from this thread, you'll get 512 x 256 female shirt and 512 x 512 female pants, but a lot of the issued pants textures are 256 x 256. You can actually use 128 x 128, 256 x 256, 512 x 512 or 1024 x 1024 and the software will scale it to fit. If you're using a pattern like camouflage and cloning in from a sample image (again, examples in my thread), you should use 512 x 512 pants to go with 512 x 256 shirt in order to get the blobs the same approximate size.
There are a few images in there which are huge, because I wanted the resolution for jewellery. Note that there is an upload file size limit and there are a lot of textures going up, so it would be sensible to restrict your use of 4x and 16x pixel-count textures to small areas of high definition, like jewellery and small, intricate tattoos, rather than using them for generic stuff. I did a shirt that way for the sake of the moon and sparkle, but I generally stick to the 512 x 256 shirts.
There's no bump-map, just colour. It actually goes on skin-tight. The 3D effect is achieved using 10% to 20% black in the clear space under the item, just a pixel or two wide, and a cloth-not-body-paint effect comes from drawing wrinkles on with Dodge and Burn tools, and can also be enhanced by using a simple pattern of similar shades not a single colour. See those "talk to the face" shirts, the red and glittered dresses and the sexyoldjoe shirt for examples.
Note that the UV map layer is not quite accurate, especially at the shoulders and at the break between arm and body, so you may find you need to colour in pixels that appear to be off-model to complete an item and delete other off-model pixels to remove a stripe from the side of an arm or neck.
The software uses pixel sampling, not averaging, so a dark area with single bright pixels will sparkle as the pattern of sampled pixels shifts around and includes or excludes the bright ones. This is a lot more effective when viewed by someone else further away than the software lets you put your own camera.
By manually editing the myinfo.ini file, as per this thread and the
more recent one, you can wear underwear, outerwear and tattoos interchangeably. This means you can put underwear into the tattoo layer, outerwear into your underwear layer and a tattoo into the outerwear layer to get the tattoo on your shirt or jeans instead of on your skin. However, last time I was playing around like that I found that the crotch area of underwear becomes invisible when outerwear is worn, so you might want to restrict yoruself to doing shirts that way. You can also use the "wrong" texture for shoes to mix styles and colours. I haven't tried it yet but I presume you can use a square hair texture as a shoe texture if you really want to. You never know. It
might be really cool, or something. See my thread, page 6, for me playing with this.
If you plan on doing a complicated two- or three-part texture, note that the distances between corresponding vertices around the waist on the pants and shirt textures are
not the same. A single image pasted relative to one anchor point, e.g. front centre, will not quite line up.
Elsewhere, when wrapping over the edges of a texture, e.g. up right-hand side of torso and insides of arms and legs, the same thing occurs. This is particularly significant at the neck, the lower part of which is drawn two very different heights in the UV map. Count vertices from an obvious line, e.g. waist or ankle, to get a corresponding pair, and go by fractions of the distance to the next one.
If you draw a straight line along one polygon edge or within one polygon, it'll be straight, but if you draw it on or in two or more it could develop a stretch and/or kink because the polygons all stretch differently to fit the avatar. You might find that knees and elbows are not where you'd expect, too.
There's no way to usefully sell a finished texture, because people can't see you wearing it unless they have it too. You could try asking for PayPal donations in return for custom work, but you'll get gazumped by Rudy, blujns, me, steph, vixen, verycherrie, Monicka, sadwanker, sicklittlepig, TheAnimal and a few others all doing it for FUN.
Have a read through threads. There is random info and discussion in many of them, including mention of the
upload texture feature.