The easiest way is to download the packs available, then you just have to place them in the correct folder...
In this forum there is a couple of packs ready for download with the english competetion logos, look for them first...
If you want to create your own config file with team backgrounds you need to copy a config file into your folder with the pictures you downloadet (high resolution), name the folder team backgrounds.
This is the line you need to edit in the config file for each team!
<record from="brondby" to="graphics/pictures/team/496/background"/>
Its important that you name the picture the same as you call it in the config! You also need the clubs ID which is displayed if you tick "show unique id's" in preferences in the game... (in this case 496)...
Also you need to place the pictures in the right directory for them to display in the game
My documents/Sports Interactive/FM 2007/graphics/pictures/team backgrounds
If there is no graphics and picture folder, then create them yourself...!
Finally you have to untick "skin cache" in the game, and tick "reload skin", otherwise they might not display even though you made all other steps correct...
If you want to put other pictures in the game, you just replace "team" in the config with player, stadium, comp etc... (Remember the ID's)