Here's the v0.2 of the filter:

{code}
/**
 * Image Filter for SnipSnap Blog/Wiki
 * 
 * Copyright 2006-2007 Paulo Abrantes (pabrantes@pabrantes.net)
 * 
 * --LICENSE NOTICE--
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 * --LICENSE NOTICE--
 *
 */

package org.snipsnap.pabrantes.filter;

import java.sql.Timestamp;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.radeox.filter.Filter;
import org.radeox.filter.context.FilterContext;
import org.radeox.filter.regex.RegexReplaceFilter;
import org.snipsnap.app.Application;
import org.snipsnap.render.filter.context.SnipFilterContext;
import org.snipsnap.snip.Snip;
import org.snipsnap.snip.SnipSpace;
import org.snipsnap.snip.SnipSpaceFactory;

public class SmileFilter extends RegexReplaceFilter implements Filter {

	private static Log log = LogFactory.getLog(SmileFilter.class);

	private static Snip snip = null;

	private Timestamp lastModificationDate = null;

	public SmileFilter() {
		super();
	}

	private Snip getSnip() {
		if(snip==null) {
			String snipRepository = Application.get().getConfiguration().get(
					"app.smileRepository");
			if (snipRepository != null) {
				SnipSpace space = SnipSpaceFactory.getInstance();
				snip = space.load(snipRepository);
				if (snip == null) {
					log.warn("It seems the snip is invalid, maybe it still has to be created!");
				}
			}
		}
		return snip;
	}

	private void loadSmiles() {
		clearRegex();
		this.lastModificationDate = snip.getMTime();
		String content = snip.getContent();
		String[] smiles = content.split("\\\r\\\n\\\r\\\n");
		for (int i = 0; i < smiles.length; i++) {
			String[] components = smiles[i].split("=");
			addRegex(components[0], "<img src=\\\"space/" + snip.getName() + "/"
					+ components[1] + "\\\" />");
		}
	}

	private void checkForModifications() {
		Snip snip = getSnip();
		if (snip != null && snip.getMTime() != lastModificationDate) {
			loadSmiles();
		}
	}

	@Override
	public String filter(String text, FilterContext context) {
		Snip snip = getSnip();
		SnipFilterContext filterContext = (SnipFilterContext) context;
		if (snip != null && !filterContext.getSnip().getName().equals(snip.getName())) {
			checkForModifications();
			return super.filter(text, context);
		}
		return text;
	}

}
{code}

Modifications:

- You now define which snip will have the regex=image in the Config snip, under the property app.smileRepository. Example, "app.smileRepository=mySmiles" will point to space/mySmiles snip.

- The filter as the following exceptions:
** If the snip being rendered is the smile repository the filter isn't applied. So if a regex and the text are actually the same it doesn't get filtered into an image, becoming IMAGE=imageName on the configuration snip - this was happening to me while testing for example the :S smile.
** If no property at the configuration file was defined filtering is skipped
** If a property at the configuration was specified but with a non-existing snip, filtering will be skipped __but__ problem logged.

- If the repository is modified on the fly on the Config property a container restart is needed, no hot swap here I didn't thought it was needed.