I'm not sure if this is something peculiar to my setup or if it's a SW thing - but when I use a png file as a sketch background, it comes in with a different size to what the file actually is. ie. The image is 2097 x 1632 png file. Bring it into SW 2011 and it comes in as 2048 x 1593. The odd thing is that if I convert it to a JPG or TIF or any other format it comes in with the correct 1 pixel = 1 mm as described in the documentation.
Why is this happening?
I know it's not a big deal but I've not been able to track down why it only happens with png's.
In case it's important - the png's are saved from photoshop cs5. Is there some cond of margin built into png's that I'm not aware of but SW is?