How to change Logo size

Hi,

I replaced the Logo0, logo1, etc png with our logo. Although when i was working on my laptop the Logo was showing fine, now that i am working in our webserver the logo doesn't show at all. Why is this? Could it be due to different dimensions (480 x 210)? (Although the dimensions on our logo on the webserver are exactly the same as on my localhost installation, where in the second case, eveything was working fine)

Suggestion plz...

For others that may read this , if your site is linux hosted then paths(urls) are case sensitive , so if you changed the case of logo file name that can cause that.