Icon for Issue Operations Bar web-item

I’ve been trying to add a icon to my web-item button. I’ve tried following the documentation and answers to old topics but they don’t seem to work. Can someone help me out?

I’ve tried a web-resource, a regular resource and making the link “/images/excel_icon.png”.

Atlassian-plugin.xml

<web-resource key="export-issues-resource" name="tigExportIssuesExtension Admin Configuration Resources">
    <context>atl.general</context>
    <resource type="download" name="images/" location="/images"/>
</web-resource>

<resource type="download" name="images/" location="/images"/>
<web-item key="export-issues-tools" name="Export Issues tools button" section="jira.issue.tools" weight="200">
    <icon height="16" width="16">
      <link>/download/resources/tigExportIssuesExtension/images/excel_icon.png</link>
    </icon>
    <description key="export-issues-tools-desc">General description</description>
    <label key="tigExportIssuesExtension.tools-title" />
    <context-provider class="tig.jira.extension.tigExportIssuesExtension.context_providers.ExportIssuesToolsContextProvider"/>
    <link linkId="tigExportIssuesExtension.settings-link">/plugins/servlet/ExportIssuesServlet?$issueKey</link>
    <condition class="tig.jira.extension.tigExportIssuesExtension.conditions.ProjectAccessCondition"/>
  </web-item>

  <servlet key="export-issues-servlet" class="tig.jira.extension.tigExportIssuesExtension.context_providers.ExportIssuesExcelServlet">
    <url-pattern>/ExportIssuesServlet</url-pattern>
  </servlet>