Background Image changing Problem

[iamjayakumars]

Hi, After changed my theme i try to change my background theme via customize theme in Appearance-> Manage theme.
I try to select a file(upload) and drag & drop image, its not uploading to server.
i checked with other themes also its not working.

[iamjayakumars]

I try to change the Background theme via Apperance -> Background.
Now the image is uploaded but its not displaying in site

[SergeyBiryukov]

Could you provide some steps to reproduce the issue on a clean install (with Twenty Twelve or Twenty Eleven theme activated and all plugins disabled)?

Currently this sounds like a support issue, so the support forums would be the proper place for troubleshooting: ​http://wordpress.org/support/

[iamjayakumars]

Its clean install only.
Wordpress need more security i can able to create a username & password with one character/number.

[MikeHansenMe]

I agree with Sergey that is sounds like a support issue. I was not able to reproduce anything like what is described (switching between Twenty Twelve and Twenty Eleven). Also, not sure what single character user/pass has to do with background image.