Colour
Do you know the colour specs of the final prints? Are they going to print in millions of colours($$$) or 12 colours(cheap). Ask them for examples before you buy, if the final vinyl looks like a photograph then you should have no problems with any image. If the colours are very limited then you will have to choose your photos carefully or they will look flat.
Ask for proofs before the final print, look at a sample of YOUR photo on their vinyl before they print full size. It will save time, money and aggravation.
So based on your window sizes a full size window would have a aspect ratio of around 5 x 7 or half size would be 5 x 3.5 That is assuming the windows stand tall or are they wide/landscape?
Keith
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