Comment # 1 on bug 1084013 from Andreas Stieger

Isn't a lack of image display capability in Evolution a bug in evolution? 
Anyway, this can be achieve as local configuration, and does not need to be in
the package. See below. Will that suffice?

$ cat ~/.local/share/applications/firefox-img.desktop 
[Desktop Entry]
Categories=Network;WebBrowser;GTK;
Encoding=UTF-8
Name=Firefox (img)
GenericName=Web Browser
Comment=Web Browser
TryExec=firefox
Exec=firefox %u
Icon=firefox
Terminal=false
StartupNotify=true
MimeType=image/jpg;image/jpeg
Type=Application
NoDisplay=true