Try this:
Take an image(jpeg, gif whatever) that contains some lines . Cut the image in
2 smaller images and create an html and put those images in a html table so the
initial image will be created. Now let's say take the left image and insert it
in a swf flash file. In flash set the image so it will not be altered, that
means 100% image quality, 100% image render on flash settings etc. Now replace
the left image from the html file with the swf file. You will see that on the
right side of the swf file, the image seems to be upper or lower than the image
from the right. It's a small difference of 1-2 pixels, especially if you have a
line that exists both in left and right images. Any ideas why?