logo size

[icecore]

Hi

I'm trying to change logo size, i found this in header.tpl

<img class="logo" src="{$logo_url}" alt="{$shop_name|escape:'htmlall':'UTF-8'}" {if $logo_image_width}width="{$logo_image_width}"{/if} {if $logo_image_height}height="{$logo_image_height}" {/if} />

 

but where should i define logo size?

where are this variables declared?

$logo_image_width

$logo_image_height

 

thanks