desktop picture does not change from stretched to other options

[ukpt32]

Hi Have an HP Pavilion DV6 dual core running Windows 7 which is up to date. I have tried to put in a new desktop picture but even though I want it only centered, windows 7 keeps stretching it, even after I have clicked any other option and then "save changes".

Any advice please?
Thanks

[Geek-9pm]

What is the size of the picture?
What format?
Does it do this with other pictures of about the same size ans same format?
Have you tried to convert the picture to another format?
(In rare cases a picture can have corrupted information. Open it in MS Paint and save it to a new file may correct this.)