This is just practising texture painting seams and edging in blender - far from perfect, but i am slowly getting there. I just find it very difficult to control both the model and the texture stamp and not get confused with all the buttons needed to be pushed, but practice makes perfect i guess - which i still need lots of .
The image for the diffuse i found on Google - I am not sure what its copy right licence is - so definitely dont use this for commercial works. its a very simple shirt and the diffuse texture can easily be modified - in which case the shirt itself you can use for what ever you want.