Q: How I can change my profile photo on iMessage?

That is controled via the photo you have set for yourself in Contacts

Using FaceTime http://support.apple.com/kb/ht4319

Troubleshooting FaceTime http://support.apple.com/kb/TS3367

The Complete Guide to FaceTime + iMessage: Setup, Use, and Troubleshooting

http://tinyurl.com/a7odey8

Troubleshooting FaceTime and iMessage activation

http://support.apple.com/kb/TS4268

Using FaceTime and iMessage behind a firewall

http://support.apple.com/kb/HT4245

iOS: About Messages

http://support.apple.com/kb/HT3529

Set up iMessage

http://www.apple.com/ca/ios/messages/

iOS 6 and OS X Mountain Lion: Link your phone number and Apple ID for use with FaceTime and iMessage

http://support.apple.com/kb/HT5538

How to Set Up & Use iMessage on iPhone, iPad, & iPod touch with iOS

http://osxdaily.com/2011/10/18/set-up-imessage-on-iphone-ipad-ipod-touch-with-io s-5/

Troubleshooting Messages

http://support.apple.com/kb/TS2755

Troubleshooting iMessage Issues: Some Useful Tips You Should Try

http://www.igeeksblog.com/troubleshooting-imessage-issues/

Setting Up Multiple iOS Devices for iMessage and Facetime

http://macmost.com/setting-up-multiple-ios-devices-for-messages-and-facetime.htm l

FaceTime and iMessage not accepting Apple ID password

http://www.ilounge.com/index.php/articles/comments/facetime-and-imessage-not-acc epting-apple-id-password/

Unable to use FaceTime and iMessage with my apple ID

https://discussions.apple.com/thread/4649373?tstart=90

How to Block Someone on FaceTime

http://www.ehow.com/how_10033185_block-someone-facetime.html

My Facetime Doesn't Ring

https://discussions.apple.com/message/19087457

To send messages to non-Apple devices, check out the TextFree app https://itunes.apple.com/us/app/text-free-textfree-sms-real/id399355755?mt=8

How to Send SMS from iPad

http://www.iskysoft.com/apple-ipad/send-sms-from-ipad.html

 Cheers, Tom

open Face time...
check whether your contact is there on the list...if its there click your contact..on the right side u will find the edit option..now u can edit ur photo all other stuff!!!
If u dont have ur contact on the contact list then create a contact of your own with apple ID and edit it...GOOD luck.

I <3 