Adobe Photoshop Tutorial –
Create a new file with transparency
1) Create a new file. On the Photoshop toolbar select File > New
2) Set the transparency options. In the New dialog box, set your width, height, and resolution as usual. Then, under Background Contents select Transparent from the drop-down menu.
3) Create your image. Add text to your image, copy your design from another file or program, etc. Make sure the “checkerboard” pattern is showing everywhere you want the shirt color showing through!
4) Save your image as transparent PNG. On the Photoshop toolbar select File > Save As
5. Under the Format drop-down menu, select PNG.
6. CLick Save and the PNG Options window will appear. Leave the default setting to None and click OK.