About MichaelSoft's note "Imageinterlace($im, 1) creates a JPG which is first loaded completely before showing anything":
Actually, that's not completely true.
This only happens with Internet Explorer (any version, for the time being) as it doesn't seem to support progressive displaying and rather shows the image, when it's 100% done with loading. Other browsers (Mozilla, Mozilla Firefox, Opera, Konqueror, etc.) do their job as they're supposed to do: Displaying a very low-res image, then overlaying a midlow-res image (while loading), and then displaying more and more details.
