Pictures of generic things like football stadiums and club crests tend to be used freely - and as long as you are not bringing the clubs name into disrepute - then most sporting organisations are OK with it. Typically I will go to the club website to find an image.
There are exceptions - a few years back FIFA wrote to me saying that I did not have approval to use a picture of the football world cup (I was using it as a visual enhancement / link to World Cup picks) and I had to change to a generic trophy ... I chose this toy one.
When it comes to sports action and specific player pictures then I strongly advise NOT to take pictures directly from websites - many big news sites pay large royalties to be able to use sports action shots.
You may be able to take a "snip" of part of the picture, change the file-type and save it as your own file and be OK as it looks like a new image, especially if you run it through some sort of colour enhancement or filter ... is it legal? Grey area.
Take a look at this page as an example.
http://www.goonersguide.com/arsenal-...ting-picks.php
I have the following :
1/ club crest
2/ stadium image
3/ head banner with photo
4/ section banner with photo
None of the photos are my "clicks" but I've use some generics and taken elements of other shots and created something new.
As far as I am concerned - all are OK and being used fairly.
(But it's still a bit grey - and probably only OK because no-one will recognise their own original work)