docs: add README documentation for sign_image_field module

README.md

@@ -0,0 +1,29 @@
+# Sign Image Field
+
+Add an Image field type to Odoo Sign templates to allow users to securely attach/upload images into documents.
+
+## Features
+
+- **New Field Type**: Adds an "Image" field to the Sign template editor toolbar.
+- **Image Upload Integration**: Allows signers to click the field and upload local images (JPEG, PNG, GIF) directly onto the document.
+- **Dynamic Positioning**: Place the image field anywhere on your document just like any other sign field.
+- **Data Extensibility**: Integrates securely with Odoo's core `sign.request.item.value` models to retrieve images directly inside signed PDFs.
+
+## Usage
+
+1. **Edit a Template**: Go to Sign -> Templates and open a template for editing.
+2. **Drag & Drop**: Drag the "Image" field from the left toolbar onto your document.
+3. **Configure**: Click on the image field to label it appropriately.
+4. **Save**: Save the template and send the sign request.
+5. **Sign**: The recipient can click on the image box to browse their system for an image to upload.
+
+## Technical Details
+
+- **Module Name**: `sign_image_field`
+- **Dependency**: `sign` (Enterprise)
+- **Odoo Version**: 19.0
+- **Authors**: Suherdy Yacob
+
+### Technical Notes & Bug Fixes
+
+- **Trailing Whitespace Patch (`PDFIframe` crash)**: Custom template components injected into the Sign module canvas can sometimes incur trailing QWeb whitespace `Text` nodes. This causes Odoo’s native JS to crash on `target.lastChild` reference when opening documents. This module implements a frontend Javascript patch (`sign_image_upload.js`) wrapping Odoo's native `insertAdjacentHTML` method to instantly trim whitespace nodes upon injection. This ensures robust application stability without diverging core Odoo source code.