Do not forget to check this :
A Cross-browser JavaScript DHTML Library which adds Drag Drop functionality and extended DHTML capabilities to layers and to any desired image, even those integrated into the text Drag & Drop Image flow.
Window resize events! Image resize…
http://www.walterzorn.com/dragdrop/dragdrop_e.htm

Linux:
Browsers based on the Gecko-engine (Mozilla, Netscape 6+, Galeon…), Konqueror 3.2+, Netscape 4, Opera 5+.
Windows:
Gecko browsers (Mozilla, Netscape 6+, Phoenix…), Netscape 4, Opera 5, 6 and 7, Internet Explorer 4+.
Other Systems:
Mac Safari works fine. Assuming that their behavior is essentially the same as with their Linux and Windows counterparts, I’ve given Gecko browsers, Netscape 4 and Opera 5+ unlimited access to execute the Drag and Drop JavaScript.
wz_dragdrop.js automatically re-integrates images and relatively positioned layers into the logical structure of the page. That is, back into the page flow even if line-breaks, table-sizes etc. have changed. Items that have previously been dragged keep their relative offset from their – also recalculated – default location within the page flow (accessible, by the way, through the defx and defy properties of each item). That means: A user won’t break the API if they decide to resize their browser window.