How to increase Page Speed

Google Page Speed addon for Firebug

Says me for this page /pg/groups/world/
   
   
Specify image dimensions
A width and height should be specified for all images in order to speed up page display. Specifying image dimensions prevents the browser from having to re-position the contents of the page.

The following image(s) are missing a width and/or height:

# /community/pg/groupicon/4893/small/default.jpg
# /community/pg/groupicon/3388/small/default.jpg
# /community/pg/groupicon/3012/small/default.jpg
# /community/pg/groupicon/2444/small/default.jpg






And here are the results for elgg community for grouppage
/pg/groups/world/

[Score: 0%]
   
   
Specify image dimensions
A width and height should be specified for all images in order to speed up page display. Specifying image dimensions prevents the browser from having to re-position the contents of the page.

The following image(s) are missing a width and/or height:

    * /_graphics/elgg_toolbar_logo.gif
    * /pg/groupicon/212846/small/default.jpg
    * /pg/groupicon/212067/small/default.jpg (3 uses)
    * /pg/groupicon/211069/small/default.jpg
    * /pg/groupicon/184041/small/default.jpg (2 uses)
    * /pg/groupicon/20578/small/default.jpg
    * /pg/groupicon/12/small/default.jpg (8 uses)
    * /pg/groupicon/165444/small/default.jpg (2 uses)
    * /mod/groups/graphics/defaultsmall.gif (8 uses)
    * /pg/groupicon/7/small/default.jpg (3 uses)
    * /pg/groupicon/19/small/default.jpg
    * /pg/groupicon/15815/small/default.jpg (6 uses)
    * /pg/groupicon/52477/small/default.jpg (3 uses)
    * /pg/groupicon/23300/small/default.jpg (2 uses)
    * /pg/groupicon/323/small/default.jpg (2 uses)
    * /pg/groupicon/215680/small/default.jpg (2 uses)
    * /pg/groupicon/179063/small/default.jpg
    * /_graphics/powered_by_elgg_badge_drk_bckgnd.gif

 

My question is: Wher can I specify image dimensions for small, tiny, large... icons for groups and users?