x2_many_media_viewer

The Extra Media block on a product template is technically just a one2many to product.image shown as an embedded kanban. What makes it feel like a gallery manager is this widget. x2_many_media_viewer extends the standard x2many field and overrides exactly one interaction: the Add button no longer creates an empty row, it opens the html editor's media dialog with the Images and Videos tabs and multi-select enabled.

From there the widget translates dialog picks into records. A video pick becomes a new line whose name is platform - [Video] and whose video_url receives the normalized player URL. An image pick is looked up in ir.attachment, its base64 payload read, and a new line is created with the data written into every field of the sub-view that matches the hardcoded list image_1920, image_1024, image_512, image_256, image_128, plus the file name.

The template also moves the kanban renderer above the control panel, which is why the gallery reads pictures first, buttons second, unlike every other x2many.

Product pages sell with media, and this widget is what makes maintaining that media tolerable at catalog scale. Merchandisers pick a dozen shots in one dialog pass instead of creating rows one by one, videos drop in by pasting a YouTube or Vimeo link, and the same flow covers per-variant galleries, the red one shows red photos.

The convert_to_webp option is the quiet page-speed lever: every upload is transcoded to WebP with resized renditions, typically cutting image weight substantially versus JPEG at similar quality, with JPEG twins retained for consumers that cannot read WebP, like PDF reports. Core switches it on for both eCommerce galleries, so a stock Odoo shop gets modern formats without anyone thinking about it. If your storefront's Lighthouse score complains about image formats, checking that your custom galleries pass this option is the two-minute fix.

The core usage, from the product form

<field name="product_template_image_ids" mode="kanban"
       add-label="Add Media" nolabel="1"
       widget="x2_many_media_viewer"
       options="{'convert_to_webp': True}"/>

The variant form repeats the same element on product_variant_image_ids. add-label renames the dialog trigger, and the WebP option is on in both core usages.

A custom gallery model

# fields your model needs for full behavior
name = fields.Char()
video_url = fields.Char()
image_1920 = fields.Image(max_width=1920, max_height=1920)

Mirror product.image's shape, then use the widget on the one2many exactly like core does.

The WebP pipeline is copied, per the source's own comment, from the image field's upload handler, and it is worth knowing what it actually creates. For each picked image that is neither GIF nor SVG, the browser draws it on a canvas at the original size and again at 1024, 512, 256 and 128 where smaller than the original. Each size is exported twice, once as WebP and once as JPEG, and stored via ir.attachment.create_unique as attachments chained to the first WebP; the JPEG twins exist because PDF reports cannot embed WebP. The record's image fields then receive the full-size WebP data. One behavioral footnote: Odoo 18 exported WebP at an explicit 0.75 quality, 19 calls the browser default instead, so the same upload can weigh slightly differently across versions.

The other sharp edge is attachment provenance. The dialog can hand back URL-type attachments, common with demo data, which have no binary payload. The widget detects the missing data and refuses the pick with a warning naming the attachment, and the source carries a TODO admitting URL attachments are simply unsupported. Re-uploading the file turns it into a binary attachment and unblocks the pick. Note also that the rejection happens mid-loop, so in a multi-pick the files before the URL attachment are added and the rest are abandoned.

Odoo 20 is expected at Odoo Experience in Brussels, 24 to 26 September 2026. We read the widget on the public development branch at the time of writing; the branch is unstable and can change before release.

The development branch grows the widget considerably: three new undocumented options appear next to convert_to_webp, force_create, set_attachment_id and only_image, the last hiding the Videos tab; the widget starts declaring relatedFields so name, image_1920 and video_url (or attachment_id in attachment mode) are auto-loaded instead of relying on the sub-view; video picks now also fetch the platform thumbnail and store it as the record's image; and the whole resize pipeline moves to a shared saveMultipleAttachments helper in web core. We re-verify after release.