Few quesitons in regards to printing. Is there an online table that shows you your maximum (before the pixels become too obvious) print size in relation to the resolution of your images or is there a basic rule of thumb or formula for working it out. Obviously all print shops are not the same, so what do I look for when selecting a place to print upwards of 10x8?? At what size to prints become labeled as "poster" size?? Cheers.