  Web accessible content stored in obscure, unpopular or obsolete formats
represents a significant problem for digital preservation. The file formats
that encode web content represent the implicit and explicit choices of web site
maintainers at a particular point in time. Older file formats that have fallen
out of favor are obviously a problem, but so are new file formats that have not
yet been fully supported by browsers. Often browsers use plug-in software for
displaying old and new formats, but plug-ins can be difficult to find, install
and replicate across all environments that one may use. We introduce Grace, an
http proxy server that transparently converts browser-incompatible and obsolete
web content into web content that a browser is able to display without the use
of plug-ins. Grace is configurable on a per user basis and can be expanded to
provide an array of conversion services. We illustrate how the Grace prototype
transforms several image formats (XBM, PNG with various alpha channels, and
JPEG 2000) so they are viewable in Internet Explorer.
