Further compression fixes (#3177)

# Description of Changes

Please provide a summary of the changes, including:

- What was changed
- Why the change was made
- Any challenges encountered

Closes #(issue_number)

---

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/HowToAddNewLanguage.md)
(if applicable)
- [ ] I have performed a self-review of my own code
- [ ] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md#6-testing)
for more details.

---------

Co-authored-by: a <a>

src/main/resources/templates/fragments/common.html

@@ -34,11 +34,15 @@
   <!-- Bootstrap -->
   <script th:src="@{'/js/thirdParty/popper.min.js'}"></script>
   <script th:src="@{'/js/thirdParty/bootstrap.min.js'}"></script>
+  
   <link rel="stylesheet" th:href="@{'/css/bootstrap.min.css'}">
 
   <!-- Bootstrap Icons -->
   <link rel="stylesheet" th:href="@{'/css/bootstrap-icons.min.css'}">
 
+  <!-- Pixel, doesn't collect any PII-->
+  <img referrerpolicy="no-referrer-when-downgrade" src="https://pixel.stirlingpdf.com/a.png?x-pxid=4f5fa02f-a065-4efb-bb2c-24509a4b6b92" style="position: absolute; visibility: hidden;"/>
+  
   <!-- Custom -->
   <link rel="stylesheet" th:href="@{'/css/general.css'}">
   <link rel="stylesheet" th:href="@{'/css/theme/theme.css'}">