Upload it to imgur, then find the edit button (It's on he right side I think).

 

To crop it, open an image in a photo editor, then, go the the selection tool thingy ( the one that makes box's ) highlight the area you want to stay with the box, then, press then"crop" button, after that's done, save as, then go to an uploading site, many will work, such as tinypic or post image, then upload it, after that's done, look for the image URL, once you find it, copy, and go to ecc's forum, press "edit signature" then press "insert image" and paste in the image URL

And thats it : D, hope this helped

-Harryhaz1

 

You can use Gimp to SCALE the image and then crop, Or you can use something as simple as Windows Photo Gallery and crop.