If you are using IE8 and are having problems with posting pictures, using smilies etc with either posts or your signature, you may need to switch to Compatibility View . The developers will be making yuku compatible with IE8, but until then, you may need to use Compatibility View.

Internet Explorer 8 is a new release and some websites may not yet be ready for Internet Explorer 8. Click the Compatibility View toolbar button to display the website as viewed in Internet Explorer 7, which will correct display problems like misaligned text, images, or text boxes. This option is on a per site basis and all other sites will continue to display with Internet Explorer 8 functionality........

The Microsoft page linked to above has pictures on how to switch to Compatibility View and how to maintain a list of sites that work better in IE7