We have a new feature where resizing your image on a 3'rd party is not necessary.
Copy the URL of the image onto your post.
Mozilla Firefox Users - Right click on image -> View Image Info -> Location = The Image URL
Internet Explorer Users - Right click on image -> Properties -> Copy and paste the URL
Next, highlight your posted URL and click on the ImgR tags right above the post section.

Finish your post and click submit! Your image will now be resized to standard board dimensions. The image posted, can be viewed in full size dimensions if you click on the posted image.