We need images/designs in Vector format (CorelDraw, Adobe Illustrator)
versus a "Bitmap" format (internet images, .gif, .jpg, .bmp, jpeg,
etc). If you are using a "scanned image" it is more than likely a
bitmap.
The
best file formats to use for screen printing are: .cdr
(CorelDraw), .eps (encapsulated
postscript) or .ai
(Adobe Illustrator) Other files can be used, however, to
convert them is time consuming and can be costly.