Comment 18 for bug 672019

fixed version (manually snapped top left corner of the imported image to the SVG pixel grid (moved to new layer))

Underlying issue: the document page was resized to the imported image without having it aligned to the pixel grid first:

  <g
     inkscape:label="Layer 1"
     inkscape:groupmode="layer"
     id="layer1"
     transform="translate(-240,-799.36218)">

which then causes the image to be off of the SVG pixel grid if rendered as SVG on-canvas (but not when exported to PNG because both the page size and the image have integer pixel sizes):

    <image
       y="799.36218"
       x="240"
       id="image3289"
       xlink:href="data:image/png;(…)"
       height="40"
       width="300" />

AFAIU the problematic value triggering the on-screen antialiasing are both y-values (for the layer transform as well as the image y-coordinate).