Picture or transparent instead of color on a menu..

I seem to have managed most of the pictures (instead of colors) in my forum... except one!!
This is where I need your (CSS propably) help.

I need the menu to have a picture (of my choice), or be transparent on the picture below, instead of that awful white background...

Spoiler:

Hi,

You want your drop down menu in topic to have a bg picture?

Try adding this to CSS and change the photo link

Code:

.popupmenu li {
    background: url('http://r20.imgfast.net/users/2015/13/58/34/avatars/151-62.jpg') !important;
}

It does look a lot better Nera but... it seems to leave some white lines... hmmmm

Question 1
Is there a way to make it transparent?
Is there a way to remove the white lines?

Spoiler:

Question 2
Can you also make me a CSS code for background or transparency on my smilies box?

Spoiler:

hmm...this seems like a very tricky situation.

the answers above should probably be answered. ^^^

I removed the old icons because of their size... So that issue is solved!

Now... all I need is a background or transparency on my smilies box.

Hi, try this for the smileys:

Code:

#smiley-box {
    background-color: transparent;
}

Didn't seem to work...
Can you try a code for a background?