Comment 3 for bug 672135

Just "me too" style comment. LibreOffice has a really nice PDF export dialog allowing to set various aspects of exported PDF, including DPI of exported bitmaps, lossless or JPEG compression (with quality) etc.

Currently one of options how to get out of Inkscape with bitmaps in particular DPI is to save as SVG, import into LibreOffice Draw, export as PDF from LO.
On the internet are floating suggestions to set raster DPI on import. That is just a suboptimal solution as doesn't allow to export copies with different DPI settings (i.e. small PDF for preview, large DPI PDF for printing).