Smart Preview - Images under 2560/2540 long side.
Q1 - I have seen posts suggesting the Smart Preview is limited to 2560/2540 pixels on the long side meaning that if the original is less than that that is the size of the Smart Preview, so for example a 2000 pixel image on the long side will have a Smart Preview that is 2000 pixels and won't be upsampled. Is there anything in Adobe's documentation that confirms this? I have not found it. This matters when synching a collection to Adobe Portfolio.
Q2 - Does Adobe's documentation tell us which is correct 2560 or 2540? Doesn't matter that much but nice to know.
