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Image Field Prefill
Voxel's text, number, and date fields all have a Prefill value option — the image field doesn't. This function adds it: prefill image fields on new-post forms with a fixed image, or dynamically per user with tags like the author's avatar.
Overview
Enabling this function adds a Prefill value (VT) control to every Image field in Voxel's post type editor — the same dynamic-tag editor other fields use, with the author / site / page tag groups. It also makes Voxel's existing Default image picker work as a fallback (Voxel ships that setting but never applied it to forms).
Key Features
- The same dynamic-tag Prefill experience as Voxel's other fields
- Accepts attachment IDs (comma-separated for multi-image fields), attachment URLs, or dynamic tags
@author(avatar)prefills each submitter's own avatar — resolved per user at form load- Voxel's "Default image" setting acts as the fallback when the tag resolves empty
- Applies to new posts only — editing an existing post never overwrites its images
- Submitters can remove or replace the prefilled image before submitting
- Respects the field's max count and allowed file types
Setup Instructions
- Navigate to Voxel Toolkit → Functions and enable Image Field Prefill
- Go to Voxel → Post Types and open the post type's Fields tab
- Open any Image field's options
- Fill in Prefill value (VT) — an attachment ID, URL, or dynamic tag
- Optionally set a Default image as the fallback
- Save the post type
Prefill Examples
| Value | Result |
|---|---|
123 | Attachment #123 prefilled for everyone |
123,124,125 | Multiple images (multi-image fields) |
@author(avatar) | Each submitter's own avatar |
https://yoursite.com/wp-content/uploads/logo.png | The attachment behind that URL |
Use Cases
Placeholder Branding
New listings start with your site's placeholder image instead of an empty gallery.
Personal Defaults
Profile-linked post types prefill the author's avatar as their logo.
Faster Submissions
Fewer required uploads means fewer abandoned forms — users only replace the image if they want to.
Troubleshooting
The Prefill control doesn't appear
- Verify the function is enabled, then reload the post type editor
The form doesn't prefill
- Prefill applies to new posts only — editing an existing post shows its own images
- Confirm the tag resolves to a real attachment ID (test the ID directly first)
- The attachment's file type must be allowed by the field (JPEG, PNG, WebP)
A user's avatar doesn't prefill
- That user has no avatar set — the field falls back to the Default image, or stays empty