1.Click Start ,then click on your user account’s picture (see screenshot below),then go to step 3
2.Or open Control Panel (small icon) ,then click User accounts ,then click Change your picture
3.Click change your picture ,then you can select a picture as your user account logon picture ,then click Change picture .
Tip: You can put your own user account picture to below folder(You need show hidden files and folders):
C:\ProgramData\Microsoft\User Account Pictures\Default Pictures
The picture size should be 128×128 pixs and the type should be .bmp or .dip or .rle or .gif or .jpg, or .png