You can use this to resize them :Users may post images using only the following methods:
1. Re-size images so they are 1280x1024 (or widescreen comparable) MAXIMUM resolution when using IMG tags.
2. Include the link, but DO NOT use the IMG tags to embed the image directly into the post (obviously no image resolution restrictions with this method).
3. Post a thumbnail that links to the likes of 3rd party image hosting sites.
4. Make use of the 'Attach Files' function of the forum.
http://www.iconempire.com/pixel-editor/































