haha...
well it's called "scaling".
you know the sleeve patch on his shirt (photo_patch) is the same size as yours (real_patch).
so you know the ratio of photo_patch:real_patch.
then in the photo, measure the distance between photo_patch and shirt's edges or other features, then multiply by...
Middlesbrough 2015/16 Away Shirt #39 Jonathan Woodgate
Leeds - Newcastle - Real Madrid - Middlesbrough - Tottenham - Stoke - Middlesbrough... What a journey.
Sanfrecce Hiroshima 2015 Home Shirt #33 Tsukasa Shiotani
J. League 2015 Champions
Now competing in FIFA Club World Cup Japan 2015 along with Barcelona.
I'd say it depends on the supplier of the print. Some prints are not made to sit around for long, especially the very thin layer ones.
I just printed a 2010 Inter Milan too and it was painless.
Those that are known to have aged are selling for US$3 at my local stores (e.g. 2011 ManUtd cup...