Post a picture ON your chat box, not on your wall pages. If you are interested to know how, read on!
Go to your Facebook Account
Go to this link and if you like their service, you may like their page.
Upload whatever picture you want and fill in the captcha information.
After that you will upload the picture.
After upload, click show code and you can now select all by using CTRL-A and CTRL-C to copy it.
Paste it onto the Facebook Chat box using CTRL-V and add whatever caption or text you want behind it.
Click enter and you are done, here's a screenshot:
Hope it will work for you and enjoy!
Encountered any problems or feedback? Feel free to drop a comment below!