Comment 22 for bug 171390

Fyi, for those looking for such a feature, there is an extension which provides JPG export.

Oh, well actually I found 2. I'm not sure if they both work with the current version of Inkscape. If anyone finds out, maybe you could add a comment here? Anyway for what it's worth, here they are:

https://github.com/giacmir/Inkscape-JPEG-export-extension
https://github.com/sepastian/inkscape-svg2jpg

Instructions for installing external extensions: https://inkscape.org/en/learn/faq/#how-install-new-extensions-palettes-document-templates-symbol-sets-icon-sets-etc