Re: removing a white background in a product shot in photoshop or PSP
Rodney,
I am by no means a photographer, so take this with a grain of salt, but I have learned a couple of things that seemed to affect the pics I take sometimes. A real photographer may totally disagree with what I'm about to write...
In your example photo of your shirt, you notice that the white sheet actually looks greyed out. I had that happen a lot myself. Plus, because the camera tries to adjust itself for the proper lighting, it always seems to give you a bad picture of the actual item, because the light is bouncing back off the white sheet. It's like taking a picture of a person with too much light in the background. You can't see their face. I've tried to adjust lighting and flash but the light still bounces back off the white sheet.
http://prairieriders.net/images/temp/t-shirts/wrinkly8nr.jpg
Here I've adjusted the levels with Photoshop so you can see how much detail is being lost in the picture of that shirt because of the way the camera is picking up the light.
http://prairieriders.net/images/temp/t-shirts/wrinkly8nr01.jpg
I'm guessing the black square on the shirt is a coverup of a design.
Anyway, I've personally found it easier to use a color other than white for the background to take the picture, which gives me much more detail in the actual item being photographed. I've used a grey or blue sheet with good results, and then later replaced the background with white or any color you wish.
Another trick I do is to get a roll of double sided tape or make "tape rolls" so it's sticky on both sides, and actually stick that t-shirt right to a wall so that is hangs nice and has no unnatural wrinkles. The tape is hidden by the shirt that way and can be adjusted, plus it's easier to frame your shot by just stepping back rather than shooting from above.
Manequins are good, and so are models. If you can't find a good looking model, or you don't prefer to have a model, you can get rid of them after the shot is taken.
Get someone to wear the shirt, take a pic, and then Photoshop them out of it. You can replace where their head came through the neck of the shirt with a neutral color, and also get rid of the background. Here is an example I did for a club vest. It's not perfect, but you get the idea.
http://www.prairieriders.net/images/merchandise/clothing/PR Vest Gray.JPG