Here is a thread on how to resize pictures
How to Resize Your Pictures
If you have a website with pictures (such as a facebook or photobucket) what I do is simply click the picture, hold the mouse button and drop it into the url/http section. The picture should show up by itself on a new page. Copy the url and paste it into the icon that has a moon with a mountain on it. That's it! when you post, the picture will show up! Hope that makes sense? c: