Created attachment 135498 [details]
Screenshot of blurry images

On HiDPI display (Dell UP3214Q) the icons on the Bugzilla start page look very blurry as seen on the attached image.

```
#enter_bug {
 background: url(../../skins/standard/index/file-a-bug.png)  no-repeat;
}
#query     {
 background: url(../../skins/standard/index/search.png)      no-repeat;
}
#account   {
 background: url(../../skins/standard/index/new-account.png) no-repeat;
}
#help      {
 background: url(../../skins/standard/index/help.png)        no-repeat;
}
```

Could please vector graphics be used or different images depending on the resolution?