Ok if it's on a file off your computer (like a icture you took on your digital camera) then you:
1. Go on www.photobucket.com or www.tinypic.com and upload it there
2. Get the code (the one that starts with
3. paste it where you'd usually paste your text.
BUT
If you want one thats ALREADY on the internet, you
1.right click the picture
2. click properties
3. copy the "url code" off there
4. paste the url code where you'd usually put the text
5. put
at the end.
Hope it helps.