There is no fast, reliable way to convert PDF to something else, since PDF was designed as an output format, and usually does not convert well to other formats.
Here are some things you can try, but don't expect perfection.
pdftohtml with
pdfreflow - converts to HTML
calibre -- will convert PDF to rtf and other formats
PDF Import Extension for libreoffice/openoffice -- convert PDFs to various WordProcessor formats
AbiWord -- a word processor with its own PDF import routine; will export to Word and other formats
For converting to Image, or just leaving as a PDF and making edits, check out
Inkscape