Can i upload a profile picture for yahoo answers through my mobile phone?

You *might* be able to, but I can't guarantee it'll work. Uploading pictures and changing avatars has always been glitchy on mobile devices, so you may just have to do everything from a computer. However, if you still want to try to change your picture from your phone, switch to "desktop mode". A link titled "Desktop" will be at the bottom of the YA page - click that. This will set everything up they way it'd look through a computer. Desktop mode allows you to bypass a lot of the over-simplification of YA mobile.

Now, you can change your avatar to either a Yahoo cartoon avatar (like the one I have) or a picture you upload yourself. You can create a Yahoo cartoon avatar at http://avatars.yahoo.com/ - after you've created it, come back here. Hover over My Activity at the top of this page and click Edit My Preferences.

Now, click the "Update photo or avatar" link. Select your avatar (make sure the orange border is around it) and click use selected photo - then click submit. (On this step, you can also upload your own picture, crop it, and use that instead of a cartoon avatar.)

Finally, click Submit (large, blue botton) at the bottom of the edit page.

Note that it may take a while for your changes to take effect. Owing to some recent on-site glitches, it may take a few hours to a couple days for your picture and name changes to work.