1. 查看这个软件中是否有图标文件
kashu:~/.local/share/applications$ dpkg -L megasync | grep icon
/usr/share/icons
/usr/share/icons/hicolor
/usr/share/icons/hicolor/128x128
/usr/share/icons/hicolor/128x128/apps
/usr/share/icons/hicolor/128x128/apps/mega.png
/usr/share/icons/hicolor/16x16
/usr/share/icons/hicolor/16x16/apps
/usr/share/icons/hicolor/16x16/apps/mega.png
/usr/share/icons/hicolor/32x32
/usr/share/icons/hicolor/32x32/apps
/usr/share/icons/hicolor/32x32/apps/mega.png
/usr/share/icons/hicolor/48x48
/usr/share/icons/hicolor/48x48/apps
/usr/share/icons/hicolor/48x48/apps/mega.png
/usr/share/icons/hicolor/256x256
/usr/share/icons/hicolor/256x256/apps
/usr/share/icons/hicolor/256x256/apps/mega.png
2. 找到图标文件位置后，把路径写入到对应的“启动按钮”文件中（图标选择32x32大小）
注：程序的启动图标一般放置在：/usr/share/applications/ 和 ~/.local/share/applications，以.desktop为后缀名的文件
kashu:~/.local/share/applications$ cat megasync.desktop
[Desktop Entry]
Type=Application
Categories=Network
Name=megasync
Exec=/usr/bin/megasync
Icon=/usr/share/icons/hicolor/32x32/apps/mega.png
示例图（点凷图片，查看高清无码原图）：
########################这是井号，免疫伤害########################
附：
当碰到有些程序的软件包名称和程序名本身不同时，如：remote-viewer，其安装的软件包并不与之同名：
kashu:~/.local/share/applications$ dpkg -L remote-viewer（所以，这样查看不到）
dpkg-query: package 'remote-viewer' is not installed
Use dpkg --info (= dpkg-deb --info) to examine archive files,
and dpkg --contents (= dpkg-deb --contents) to list their contents.
那么，就先用dpkg -S filename-search-pattern，可查找到那个程序是由哪个软件包所提供的
kashu:~/.local/share/applications$ dpkg -S remote-viewer
app-install-data: /usr/share/app-install/desktop/virt-viewer:remote-viewer.desktop
virt-viewer: /usr/share/man/man1/remote-viewer.1.gz
virt-viewer: /usr/share/applications/remote-viewer.desktop
virt-viewer: /usr/bin/remote-viewer
virt-viewer: /usr/bin/spice-xpi-client-remote-viewer
从上面的查询中可看到，是virt-viewer这个软件提供的
然后，dpkg -L remote-viewer查看软件包中所提供的图标文件
kashu:~/.local/share/applications$ dpkg -L virt-viewer | grep icon
/usr/share/icons
/usr/share/icons/hicolor
/usr/share/icons/hicolor/256x256
/usr/share/icons/hicolor/256x256/apps
/usr/share/icons/hicolor/256x256/apps/virt-viewer.png
/usr/share/icons/hicolor/24x24
/usr/share/icons/hicolor/24x24/apps
/usr/share/icons/hicolor/24x24/apps/virt-viewer.png
/usr/share/icons/hicolor/48x48
/usr/share/icons/hicolor/48x48/apps
/usr/share/icons/hicolor/48x48/apps/virt-viewer.png
/usr/share/icons/hicolor/16x16
/usr/share/icons/hicolor/16x16/apps
/usr/share/icons/hicolor/16x16/apps/virt-viewer.png
/usr/share/icons/hicolor/22x22
/usr/share/icons/hicolor/22x22/apps
/usr/share/icons/hicolor/22x22/apps/virt-viewer.png
/usr/share/icons/hicolor/32x32
/usr/share/icons/hicolor/32x32/apps
/usr/share/icons/hicolor/32x32/apps/virt-viewer.png
不错