Well since your asking, if you are going to be investing serious money into getting some high quality screenprinting done, you would want the best print possible you? We know we would, and we sure want you to have it too.
In order for us to give you the best possible print we need the best artwork you can give us. Make the image that actual size you want it at 300DPI
If you give us a postage stamp size jpg image we can't blow that up to A3 size on a tshirt without it looking terrible.
Were good at what we do, but not that good. If we ask for better artwork it's because after years of doing this we know what's goning to work or not.
So if we ask you for a better image this is why, if you don't have the skills to do this yourself
(or know a friend who can help you out!)
for a fee we can book one of our talented graphic artists to help out.
They practically bleed pixels, so they know what they are doing.